LIBRARY 

OF    THE 

UNIVERSITY  OF  CALIFORNIA. 
Class 

SENEBAL 


THE   ENGINEERING   RECORD  SERIES 


WATER-WORKS 


FOR 


SMALL  CITIES  AND  TOWNS 


BY 

JOHN    GOODELL 


-TB  R  A  .=? 

or  THE 
,.    UNIVERSITY 

or 


THE  ENGINEERING  RECORD 
NEW  YORK 


COPYRIGHT,  189$  BY  THE  ENGINEERING  RECORD 


Introductory  Note* 


The  following  notes  on  small  water-works  have  been  compiled 
to  meet  the  desire  for  such  information  which  is  shown  by  letters 
addressed  to  "The  Engineering  Record."  The  book  contains  no 
new  theories  and  no  references  to  methods  of  construction  or  de- 
sign which  have  not  proved  satisfactory  in  actual  use.  As  an 
offset  to  this  lack  of  originality  there  will  be  found  in  the  follow- 
ing pages  considerable  information  never  before  collected  in  a 
single  volume,  and  troublesome  to  obtain  elsewhere.  The  editing 
of  this  material  has  been  done  with  the  idea  of  making  the  result 
of  service  to  water-works  trustees  as  well  as  superintendents  and 
engineers;  this  will  account  for  the  attention  paid  to  some  details 
which  technically  educated  officials  may  consider  very  elementary. 


1  I  5779 


CONTENTS. 

Paga 

Chapter  I.— Surface  Water. 

The  Yield  of  Catchment  Areas— Gauging  Stream  Flow— The 
Meaning  of  Water  Analyses 9 

Chapter  II.— Earth  Dams. 

Clay — Gravel — Masonry  Core  Walls — Water  in  Earthwork — 
Cross-section  of  the  Embankment — Starting  the  Core  Wall.    23 

Chapter  III. — Minor  Details  of  Reservoirs. 

Outlet  Pipes — Gate-Houses—Waste-Weirs 39 

Chapter  IV.— Timber  Dams. 

Brush  Dams — Crib  Dams — foamed  Dams 52 

Chapter  V. — Masonry  Dams. 

Foundations— Materials—  Earth    Backing— Design— Specifi- 
cations—Rock-Fill  Dams 61 

Chapter  VI. — Special  Features  of  River  and  Pond  Supplies. 

Head- Works — Effect  of  Storage  on  Water — Odors  in  Water.  81 
Chapter  VII.— Ground-Water  Supplies. 

Methods  of  Collecting  Ground  Water — Quantity  of  Ground 

Water 88 

Chapter  VIII.— The  Utilization  of  Springs. 

Springs  in  Plains— Hillside  Springs 93 

Chapter  IX.— Open  Wells 101 

Chapter  X.— Driven  Wells. 

Sinking  Wells— Air  in  Wells— Well  Specifications 109 

Chapter  XI.— Deep  and  Artesian  Wells. 

Sinking  Wells— Specifications— Yield  of  Wells— Quality  of 

Ground  Water  .  .  123 


8  CONTENTS. 

Chapter  XII.— Pumps. 

Steam  Consumption — Power  Pumps — Details  of  the  Water 
End— Special  Power  Pumps 138 

Chapter  XIIL— The  Air  Lift 157 

Chapter  XIV.— Pumping  Stations 165 

'Chapter  XV.— Intakes  and  Intake  Pipes 174 

Chapter  XVI. — Clarification  and  Purification  of  Water. 

Turbidity — Slow  Sand  Filters — Mechanical  Filters 182 

Chapter  XVIL— The  Pipe  System. 

Flow  of  Water  in  Pipes — Data  Concerning  Pipe  and  Acces- 
sories— Submerged  Pipe — Clay  Pipes  and  Open  Channels . . .  196 

Chapter  XVIII. — Service  Reservoirs  and  Standpipes. 

Concrete-Lined  Reservoirs  —  Asphalt-Lined  Reservoirs  — 
Standpipes  and  Water  Towers — Substitutes  for  Standpipes.  218 

Chapter  XIX.— The  Quantity  of  Water  to  be  Provided. 

Relative  Capacities  of  Small  Works  for  Domestic  Supply 
and  Fire  Protection — The  Influence  of  Small  Street  Mains — 
Fire  Streams 251 

Chapter  XX.— The  Water-Works  Department. 

Financial  Considerations — Checking  Waste — Keeping  up 
the  Works 263 

Alphabetical  Index 283 


WATER-WORKS  FOR  SMALL  CITIES  AND  TOWNS. 


CHAPTER  I.—  SURFACE  WATER. 

By  surface  water  is  meant  the  water  discharged  from  the  sur- 
face of  a  catchment  area,  as  opposed  to  that  collected  from  wells 
and  galleries.  Such  surface  supplies  depend  upon  the  rainfall  for 
their  existence,  and  upon  the  natural  features  of  the  watershed  for 
their  character.  It  is  generally  an  easy  matter  to  secure  statistics 
of  the  rainfall  in  the  neighborhood  of  most  places  large  enough  to 
have  water-works,  and  from  such  statistics  and  an  inspection  of 
the  catchment  area  the  probable  amount  of  water  usually  avail- 
able may  be  determined.  It  is  sometimes  possible,  also  to  secure 
maps  of  the  watershed,  which  are  often  of  much  value  as  indi- 
cating the  sources  from  which  a  supply  may  be  obtained;  the  maps 
of  the  national  and  state  geological  surveys  are  frequently  used 
for  this  purpose. 

While  it  is  the  exception  rather  than  the  rule  that  a  survey  of 
a  watershed  for  a  small  system  has  to  be  made  with  accuracy  and 
be  mapped  subsequently,  yet  cases  may  arise  when  this  is  neces- 
sary, and  consequently  a  few  hints  are  given  here  as  to  the  meth- 
ods now  regarded  as  best  adapted  for  such  work.  It  is  pretty  gen- 
erally believed  by  engineers  who  have  done  most  work  of  this  sort 
that  the  quickest  and  cheapest  method  is  by  means  of  a  transit 
having  stadia  hairs  in  the  telescope,  the  notes  being  plotted  in  the 
field  on  a  sketchboard.  The  accuracy  of  the  stadia  was  definitely 
settled  during  the  survey  of  the  Mexican  boundary  a  few  years 
ago,  and  if  the  precautions  are  followed  which  are  recommended 
in  a  paper  on  this  survey  by  J.  L.  Van  Ornum,  Assoc.  M.  Am.  Soc. 
C.  E.  (see  the  "Transactions"  of  the  American  Society  of  Civil 
Engineers,  Vol.  xxxiv.,  p.  259),  the  topography  of  a  watershed 
may  be  taken  with  much  dispatch  and  sufficient  accuracy  for  all 


10  WATER-WORKS    MANUAL. 

purposes.  It  is  unnecessary  here  to  give  instructions  as  to  the 
method  of  making  the  stadia  survey,  but  a  few  notes  on  the  use  of 
a  sketchboard  may  be  appropriate,  as  the  published  information 
on  the  subject  is  meager  and  not  readily  secured. 

The  sketchboard  is  merely  a  portable  drawing-board  on  which 
the  transit  and  stadia  notes  are  plotted  in  the  field  as  fast  as  prac- 
ticable. These  notes  furnish  the  location  and  elevation  of  all  the 
leading  features  of  the  tract  surveyed,  and  it  is  an  easy  matter  for 
a  draughtsman  to  sketch  in  the  intervening  contour  lines  by  eye. 
One  of  the  best  sketchboards  known  to  the  writer  was  designed 
by  A.  R.  Paddock,  and  is  described  in  "The  Engineering  Record" 
for  October  31,  1891,  and  February  6,  1892.  The  top  is  a  wooden 
frame,  into  which  fit  four  small  wooden  squares.  The  top  of  each 
square  is  covered  with  drawing-paper,  which  is  turned  over  the 
edges  and  fastened  to  the  lower  surface.  When  the  four  squares 
covered  in  this  way  are  placed  in  the  frame  a  uniform  paper  sur- 
face of  about  310  square  inches  is  furnished  f or  sketching.  When- 
ever the  plotting  approaches  one  edge  of  the  board,  as  the  east, 
the  two  eastern  sections  are  transferred  to  the  west  edge  and  two 
fresh  ones  put  in  their  place.  The  field  notes  were  plotted  on  these 
tables  in  two  ways.  Some  were  laid  off  by  using  the  magnetic 
bearings  and  marking  off  the  points  with  a  card  protractor  having 
a  scale  on  one  edge,  while  others  were  fixed  by  using  a  simple  ali- 
dade consisting  of  a  metallic  triangular  scale  with  a  pair  of  sight- 
ing wires  attached.  The  cost  of  a  table  of  this  sort  was  about  $11. 

On  the  surveys  made  in  1884,  under  the  direction  of  Rudolph 
Hering,  M.  Am.  Soc.  0.  E.,  in  connection  with  his  studies  for  a 
new  water  supply  for  Philadelphia,  the  advantages  of  the  sketch- 
ing-table and  transit  method  of  surveying  were  found  to  be  as 
follows: 

"First,  the  immediate  detection  and  correction  of  errors  in 
angles  or  measures  while  plotting,  thereby  saving  delays  and  inac- 
curacies in  the  office  work;  secondly,  the  drawing  and  sketching 
of  the  contours  in  greater  conformity  with  the  shape  of  the 
ground  while  viewing  it,  and  saving  the  measuring  of  many  points 
that  would  be  necessary  in  the  case  of  office  plotting;  thirdly,  the 
possibility  of  putting  in  minor  points  by  sight  intersections,  as  on 
a  plane  table;  and  fourthly,  of  having  the  map  so  far  completed 
in  the  field  that  it  requires  little  more  than  an  adjustment  and 
transfer  by  means  of  blackened  paper  to  be  in  its  proper  form 


WATER-WORKS  W&NV&L.  It 

and  place  upon  the  section  maps.  The  results  have  so  far  been 
very  satisfactory,  the  plotting  shows  a  high  degree  of  accuracy, 
and  the  gain  in  time  has  been  considerable.  In  the  field  the  plot- 
ting parties  could,  on  similar  territory,  of  course  not  cover  as 
much  ground  per  week  as  the  others,  their  gain  being  in  office 
work.  In  fair  country  it  was  found  possible  readily  to  survey  and 
plot  in  the  field,  to  a  scale  of  400  feet  to  1  inch,  3  square  miles  per 
week,  the  party  consisting  of  the  engineer  and  one  rodman."  (Re- 
port by  Rudolph  Hering.) 

On  this  survey  the  field  table  was  15  inches  square,  and  had  a 
universal  joint  and  tangent  screw.  It  rested  on  a  very  light 
tripod.  The  sheets  of  paper  were  ruled  to  quarter-inch  squares, 
each  square  representing  a  100-foot  square  of  land.  Main  lines 
were  run  with  the  transit  by  magnetic  courses  and  stadia  in  cir- 
cuits of  1  to  3  miles,  and  these  were  immediately  plotted  to  scale 
on  the  table  standing  beside  the  transit.  The  levels  were  taken 
by  the  transit,  by  spirit  leveling  and  vertical  angles,  from  bench 
marks  established  by  a  level  party,  and  were  plotted  at  once  on 
the  paper,  so  that  the  contours  could  be  sketched  in.  Buildings, 
roads,  and  streams  were  located  by  transit  angles  and  then  plot- 
ted, or  were  sighted  from  the  table,  after  leveling  and  orienting 
tt.  Colored  pencils  were  used  to  mark  in  certain  features;  blue 
for  watercourses,  green  for  the  outlines  of  woods,  and  yellow  for 
roads. 

Of  course  it  is  not  always  convenient  to  use  this  method  of  sur- 
veying, and  when  a  sketching-table  is  not  available  a  modification 
of  the  following  method  may  be  found  advantageous.  This 
method  was  also  used  under  Mr.  Bering's  direction.  The  instru- 
ments employed  were  a  transit,  stadia  rod,  slope  level,  prismatic 
compass,  and  barometer.  Main  or  base  lines,  with  magnetic 
courses  and  stadia  distances,  were  run  over  the  territory,  so  as  to 
form  approximate  quadrilaterals  of  about  one-half  to  three- 
fourths  square  mile  each.  They  were  bounded  by  definite  lines, 
as  roads  or  streams,  tied  at  the  four  corners.  The  position  and 
elevation  of  high  and  low  points  was  taken  by  magnetic  and  ver- 
tical angles,  and  stadia  distances  directly  from  the  main  line,  if 
possible,  otherwise  a  spur  line  was  run  to  where  they  could  be 
seen.  In  thickly  wooded  regions  the  topography  was  taken  with 
the  prismatic  compass,  slope  level,  and  barometer.  Buildings 
were  located  either  by  at  least  two  magnetic  angles  from  the  base 


i2  WATER-WORKS    MANUAL. 

line,  or  one  angle  and  stadia  measurement.  Roads,  streams,  and 
such  features  were  fixed  in  the  latter  way.  Levels  were  carried 
in  the  manner  mentioned  in  connection  with  the  sketch-table 
method,  and  were  generally  found  to  check  within  a  foot  in  a 
circuit  of  2  or  3  miles.  The  vertical  angles  were  reduced  by  nat- 
ural sines  and  cosines  on  the  main  lines,  and  by  co-ordinate  paper 
protractors  as  well  on  the  laterals.  All  notes  and  sketches  were 
entered  in  a  transit-book. 

The  amount  of  water  that  may  be  obtained  from  a  catchment 
area  is  very  \ariable  and  can  only  be  estimated  roughly.  A  small 
area,  under  about  2  square  miles  in  extent,  may  be  practically  dry 
at  tinier.  Statistics  compiled  under  the  direction  of  the  Boston 
Water  Board  show  that  from  40  to  50  per  cent,  of  the  rainfall  has 
been  collected,  on  an  average,  for  many  years  on  the  watersheds 
under  its  control.  These  statistics  are  probably  the  most  com- 
plete in  this  country,  and  on  this  account  they  are  largely  used  in 
estimating  the  flow  from  catchment  basins.  The  characteristics 
of  the  three  watersheds  controlled  by  the  Boston  Water  Board  are 
described  as  follows  by  Desmond  FitzGerald,  M.  Am.  Soc.  C.  E.: 

"The  Sudbury  River  watershed  has  an  area  of  75.199  square 
miles;  the  Mystic,  26.9  square  miles;  and  the  Cochituate,  18.87 
square  miles.  The  Sudbury  is  hilly,  with  steep  slopes.  There 
are,  however,  some  large  swamps  within  its  borders.  The  Cochit- 
uate, although  adjoining  the  Sudbury,  is  entirely  dissimilar. 
The  slopes  are  flat  and  sandy.  The  surface  is  mostly  modified 
drift,  while  the  Sudbury  is  largely  composed  of  unmodified  drift. 
The  Mystic  watershed  lies  to  the  north  of  Boston,  and  about  30 
miles  distant  from  the  other  two  sources,  which  are  to  the  west  of 
the  city.  Its  surface  is  steeper  than  the  Cochituate  and  not  as 
steep  as  the  Sudbury." 

The  average  monthly  yield  per  square  mile  of  these  watersheds 
for  a  period  of  13  years  was  as  follows: 

Month.  Gallons.  Month.  Gallons. 

January    37,387,000           July 7,491,000 

February   55,056,000           August 11,399,000 

March    , . . .  71,226,000           September 10,242,000 

April   49,107,000           October 16,797,000 

May   30,406,000          November 24,787,000 

June   14,975,000           December 34,128,000 

These  figures  are  interesting  and  valuable  in  many  ways  as  il- 
lustrating the  monthly  variations  in  stream  flow  under  conditions 


WATER-WOPKS    MAX  UAL.  13 

that  will  probably  be  found  to  agree  approximately  with  those  in 
many  other  parts  of  the  United  States.  The  average  rainfall  at 
Boston  for  the  last  75  years  has  been  as  follows:  January,  3.98 
inches;  February,  3.78;  March,  4.36;  April,  4.06;  May,  3.79;  June, 
3.27;  July,  3.71;  August,  4.39;  September,  3.55;  October,  3.84; 
November,  4.31;  December,  3.96;  total,  47  inches. 

In  the  design  of  water-works  depending  upon  surface  supplies 
averages  are  not  of  as  much  importance  as  minim  urns,  and  on  this 
account  the  Sudbury  River  statistics  are  of  great  value.  They  ex- 
tend back  many  years  and  contain  records  of  two  periods  of  re- 
markable drought.  Engineers  want  to  know  the  minimum  quan- 
tities of  water  to  expect  from  a  watershed,  and  the  following  table 
is  therefore  given  showing  the  daily  flow  from  the  Sudbury  basin 
for  different  periods,  the  figures  giving  the  daily  gallons  per 
square  mile  in  the  driest  period  of  the  given  duration: 

Period.      Gallons.  Period.      Gallons.  Period.      Gallons. 


1  month  
2  months.  .  . 
3  months.  .  . 
4  months.  .  . 
5  months.  .  . 
6  months.  .  . 

44,000 
64,000 
95,000 
118,000 
131,000 
143,000 

7  months.  . 
8  months.  . 
9  months.  . 
10  months.  . 
11  months.  . 
1  year  

147,000 
181,000 
219,000 
312,000 
409,000 
497,000 

2  years  .  .  . 
3  years  .  .  . 
4  years  .  .  . 
5  years  .  .  . 
6  years  .  .  . 
7  years  .  .  . 

687,000 
764,000 
735,OOU 
769,000 
803,000 
839,000 

The  average  flow  from  the  Sudbury  River  watershed  per  square 
mile  during  the  driest  periods  of  five  years  or  less  has  been,  so  far 
back  as  records  have  been  kept,  very  much  less  than  from  the 
Croton  watershed  in  New  York,  while  the  average  flow  for  the 
whole  19  years  of  observation  on  both  basins  has  been  nearly  the 
same. 

It  is  evident  from  the  above  table  that  if  means  can  be  pro- 
vided for  storing  the  surplus  water  from  a  catchment  area  during 
the  periods  when  the  supply  exceeds  the  consumption,  it  will  be 
possible  to  satisfy  daily  drafts  of  many  times  the  yield  of  the 
watershed  during  the  driest  periods  that  are  liable  to  occur.  In 
the  "Transactions"  of  the  American  Society  of  Civil  Engineers, 
Vol.  xxvii.,  p.  265,  Mr.  Fitz Gerald  gave  a  diagram  of  the  storage 
capacity  required  to  sustain  drafts  of  100,000  to  900,000  gallons 
daily  from  1  square  mile  of  watershed  containing  various  per- 
centages of  water  surface.  F.  P.  Stearns,  M.  Am.  Soc.  C.  E.,  has 
prepared  Table  No.  1  for  the  same  purpose,  arranged  in  a  some- 
what different  manner  and  taking  evaporation  into  account. 

The  nature  of  the  investigations  upon  which  this  table  was 


14 


WATER-WORKS    MANUAL. 


based  was  explained  in  "The  Engineering  Record"  of  February 
24,  1894,  and  engineers  who  desire  to  study  the  matter  farther 
are  referred  to  that  article  and  to  the  paper  by  W.  Rippl  entitled 
"The  Capacity  of  Storage  Reservoirs  for  Water  Supply,"  which 
was  published  in  the  "Proceedings?  of  the  Institution  of  Civil  En- 
gineers, Vol.  Ixxi.,  p.  270. 

Table  No.  1. — Showing  the  Amount  of  Storage  Required  to  Make  Avail- 
able Different  Daily  Volumes  of  Water  per  Square  Mile  of  Water- 
shed (Estimating  Land  Surfaces  Only),  Collected  for  the  Effect  of 
Evaporation  and  Rainfall  on  Varying  Percentages  of  Water  Sur- 
face, not  Included  in  Estimating  the  Area  of  the  Watershed. 

«  fe  *o  05  Storage  Required  in  Gallons  per  Square  Mile  of  Land  Sur- 
face to  Prevent  a  Deficiency  in  the  Season  of  Greatest 
Drought  When  the  Daily  Consumption  is  as  Indicated 
in  the  First  Column,  with  the  Following  Percentages  of 
Water  Surfaces. 


3 


6 


10 


25 


100,000 

556,000 

3,000.000 

8,800,000 

150,000 

3,400,000 

7,100,000 

13,400,000 

. 

. 

. 

„ 

200,000 

9,400,000 

11,700,000 

18,000,000 

. 

. 

. 

0 

250,000 

19,000,000 

22,200,000 

25,400,000 

. 

. 

. 

. 

300,000 

29,800,000 

33,000,000 

36,100,000 

„ 

400,000 

52,000,000 

54,400,000 

57,500,000 

. 

. 

. 

500,000 

76,500,000 

77,300,000 

80,300,000 

. 

. 

. 

600,000 

102,000,000 

104,600,000 

107,100,000 

112,800,000 

. 

. 

700,000 

144,400,000  . 

153,000,000 

161,600,000 

170,700,000 

215,900,000 

800,000 

202,300,000 

210,900,000 

219,500,000 

228,600,000 

273,800,000 

900,000 

346,200,000 

349,200,000 

352,200,000 

353,900,000 

381,600,000 

1,000,000 

514,600,000 

516,700,000 

519,700,000 

523,600,000 

532,200,000 

The  manner  in  which  the  table  is  to  be  used  can  be  most  easily 
indicated  by  quoting  from  Mr.  Stearns's  explanation. 

"Let  us  assume  that  it  is  desired  to  know  the  yield  of  a  pond 
having  an  area  of  0.15  square  mile  and  an  available  storage  capac- 
ity of  225,000,000  gallons,  which  has  draining  into  it  1.5  square 
miles  of  land  surface.  The  amount  of  storage  in  this  case  would 
be  equivalent  to  150,000,000  gallons  per  square  mile  of  land 
surface,  and  the  water  surface  would  equal  10  per  cent, 
of  the  land  surface.  By  looking  in  the  column  of  the 
table  headed  10  per  cent.,  it  will  be  seen  that  a  storage  of 
1 50,000,000  gallons  per  square  mile  corresponds  to  a  daily  volume 
of  between  600,000  to  700,000  gallons  per  square  mile,  or  more 
exactly,  by  proportion,  to  660,000  gallons,  equal  to  990,000  gal- 
lons daily  for  the  whole  watershed.  The  results  obtained  by  this 
method  will. in  some  cases  be  practically  correct.  In  other  cases 


WATER-WORKS    MANUAL.  15 

it  will  be  necessary  to  take  account  of  local  conditions,  prominent 
among  which  may  be  leakage  past  a  dam,  or  filtration  through  the 
ground  to  lower  levels;  and  the  application  of  judgment  will  often 
be  necessary  to  determine  whether  the  watershed  under  consid- 
eration will  yield  the  same  or  a  greater  or  a  less  amount  per  square 
mile  than  that  of  the  Sudbury  Kiver." 

The  more  frequent  problem,  however,  is  to  determine  upon  the 
amount  of  storage  required  to  enable  a  definite  quantity  of  water 
to  be  drawn  from  a  given  watershed.  For  instance,  suppose 
1,000,000  gallons  a  day  are  wanted  from  a  watershed  having  a 
land  area  of  1.5  square  miles.  There  is  hardly  a  catchment  area 
large  enough  to  be  considered  as  a  collecting  ground  for  water- 
works that  has  not  some  water  surface,  and  Mr.  FitzGerald  says 
that  in  the  use  of  such  methods  of  estimating  as  are  here  consid- 
ered, it  is  of  doubtful  utility  to  consider  anything  under  2  per 
cent.  In  the  present  case  it  will  be  assumed  that  the  only  water 
on  the  catchment  area  is  a  brook  of  undetermined  but  small  super- 
ficial extent;  accordingly  2  per  cent,  will  be  assumed  as  the  water 
area.  The  amount  of  water  required  per  square  mile  of  land  area 
will  be  a  little  under  670,000  gallons.  By  interpolating  from  the 
table  it  will  be  found  that  the  storage  needed  under  these  condi- 
tions will  be  about  136,300,000  gallons  per  square  mile  of  land 
surface,  or  235,000,000  gallons  all  told.  Such  a  storage  volume, 
however,  would  require  a  water  surface  of,  say,  about  0.13  square 
mile.  This,  however,  is  about  8^  per  cent,  of  the  total  land  area, 
and  indicates  that  another  computation  will  be  needed. 

In  view  of  the  results  of  the  first  calculation  it  will  be  assumed 
that  the  land  area  is  reduced  to  1.4  square  miles  by  reason  of  the 
construction  of  the  reservoir,  and  that  the  water  area  is  10  per 
cent,  of  the  land  area.  In  this  case,  the  draft  per  square  mile  of 
land  surface  will  be  a  little  over  700,000  gallons  a  day,  and  will 
require  a  storage  capacity  of  171,000,000  gallons  per  square  mile, 
or  240,000,000  gallons  all  told.  Hence  such  a  reservoir  under  the 
conditions  assumed  may  be  considered  adequate  to  supply  the 
quantity  of  water  desired.  But  such  a  reservoir  might  prove  very 
undesirable  from  another  point  of  view,  even  if  a  location  for  it 
can  be  found. 

It  has  been  pointed  out  repeatedly  that  any  attempt  to  store 
more  than  700,000  gallons  per  square  mile  of  watershed  in  arti- 
ficial reservoirs,  under  the  conditions  obtaining  in  the  Sudbury 


16  WATER-WORKS    MANUAL. 

Kiver  basin,  will  be  very  liable  to  end  in  failure  from  the  fact  that 
during  several  consecutive  months  the  water  level  in  the  reservoir 
may  be  so  low  as  to  permit  a  growth  of  weeds  on  the  exposed 
shores,  which  will  cause  a  marked  deterioration  in  the  quality  of 
the  water. 

Mr.  Stearns  states  that  taking  everything  into  account  it  may 
be  said  the  greatest  amount  which  can  be  made  practically  avail- 
able from  a  square  mile  of  watershed  does  not  exceed  900,000  gal- 
lons per  day,  and  the  cases  are  very  rare  in  which  more  than 
600,000  gallons  per  square  mile  per  day  can  be  made  available 
when  it  is  necessary  to  store  the  water  in  artificial  reservoirs.  Mr. 
FitzGerald  states  that  it  is  impracticable  to  secure  more  than 
about  750,000  gallons  daily  per  square  mile  of  watershed  contain- 
ing 10  per  cent,  of  water  surface.  The  reason  for  this  limitation 
is  that  the  levels  in  the  reservoir  should  not  be  made  to  fluctuate 
too  much  and  that  the  reservoir  should  not  be  drawn  below  the 
high-water  mark  for  too  long  a  time. 

The  above  method  of  estimating  the  amount  of  water  which 
may  be  made  available  from  a  watershed  is  very  conservative. 
IJ  nder  the  conditions  of  rainfall  and  topography  upon  which  it  is 
based,  it  will  be  too  conservative  for  most  years.  But  a  water 
famine  is  a  serious  affair,  and  it  is  well  to  provide  against  it.  The 
modifications  of  the  method  to  suit  localities  where  the  conditions 
of  rainfall  differ  from  those  mentioned  are  matters  of  judgment 
for  which  no  general  rules  can  be  given.  It  must  not  be  forgot- 
ten, however,  that  because  the  discharge  of  small  catchment  areas 
is  liable  to  so  much  greater  variations  than  that  of  larger  basins, 
it  is  highly  important  to  avoid  overestimating  their  yield  in 
periods  of  extreme  drought.  Speaking  generally,  it  may  be  said 
that  unless  a  watershed  is  very  mountainous,  very  flat,  or  very 
sandy,  or  unless  the  rainfall  upon  it  differs  considerably  during  a 
term  of  several  years  from  the  averages  given  in  the  preceding 
discussion,  the  determination  of  the  available  supply  by  the  fore- 
going method  will  give  results  as  nearly  accurate  as  such  estimates 
can  be  made.  Moreover,  the  determination  thus  made  will  be  free 
from  the  very  frequent  error  of  exaggerating  the  amount  of  water 
that  may  be  safely  counted  upon. 

In  some  cases  there  may  be  a  brook  flowing  from  the  watershed, 
and  it  is  desirable  to  ascertain  roughly  how  much  water  is  passing 
in  it.  In  such  a  case  the  cross-section  of  the  stream  should  be 


WATER-WORKS    MANUAL. 


17 


measured  as  carefully  as  possible  at  the  lower  end  of  the  straight- 
cst  and  most  uniform  part.  Then  a  distance  of  100  feet  should 
be  measured  back  from  the  place  where  the  cross-section  was 
taken,  and  the  number  of  minutes  it  takes  several  small  pieces  of 
wood  to  pass  this  100  feet  should  be  observed.  In  this  way  the 
surface  velocity  of  the  brook  may  be  determined.  Eight-tenths  of 
this  velocity,  expressed  in  feet  per  minute,  multiplied  by  the  cross- 
section  of  the  brook  in  square  feet,  will  give  approximately  the 
discharge  of  the  brook  in  cubic  feet  a  minute.  This  method 
should  not  be  used  unless  the  100-foot  section  of  the  brook  is  fair- 
ly straight  and  differs  but  little  in  its  sectional  area  throughout 
the  distance. 

Where  greater  accuracy  is  desired  weirs  must  be  employed.    A 


Gauge  Post. 


Weir 


FIGURE  1.  -  ARRANGEMENT  FOR  GAUGING  BROOKS. 

rough  weir  can  be  made  as  shown  in  Figure  1  without  much  diffi- 
culty. The  planks  should  be  firmly  bedded  in  the  bottom  and 
sides  of  the  brook,  and  the  three  edges  of  the  rectangular  notch 
should  be  beveled  off  to  an  angle.  The  distance  from  the  sides 
and  bottom  of  the  notch  to  the  banks  and  the  bed  of  the  brook 
should  be  not  less  than  three  times  the  depth  of  the  water  above 
the  lower  edge  of  the  notch.  The  bottom  edge  of  the  notch 
should  be  perfectly  level.  Care  must  be  taken  that  water  does  not 
have  an  opportunity  of  leaking  under  or  around  the  weir.  Six 
feet  or  more  above  the  weir  a  stake  should  be  driven  firmly  in  the 
bed  of  the  brook.  When  this  is  done,  which  should  be  before  the 
planks  are  put  in  place,  the  weir  should  be  built  up,  and  the  ele- 


18  WATER-WORKS    MANUAL. 

vation  marked  very  carefully  on  the  stake  at  which  water  begins 
tc  flow  over  the  notch.  Then  a  scale  of  inches  should  be  marked 
on  the  stake  with  this  point  as  a  zero.  If  the  work  is  well  done 
this  scale  will  enable  the  depth  of  water  above  the  notch  to  be 
determined  quite  accurately.  In  order  to  determine  the  flow  over 
the  weir,  take  the  reading  in  feet  and  decimals  of  a  foot  on  the 
stake  and  then  obtain  from  Table  No.  2  the  discharge  in  cubic 
feet  per  second  over  a  weir  1  foot  long  for  that  depth.  Multiply 
this  discharge  by  the  length  of  the  notch  in  feet  and  the  result 
will  be  the  discharge  of  the  brook  in  cubic  feet  per  second.  Care 
should  be  taken  to  make  the  notch  of  such  a  size  that  the  flow 
through  it  will  not  exceed  6  or  8  inches  a  second,  if  possible. 
Notches  2  feet  long  are  best  with  depths  of  water  of  0.3  to  0.7 
foot,  3  feet  long  with  depths  of  0.3  to  1  foot,  and  weirs  5  feet  long 
with  depths  as  high  as  1.7  feet.  The  values  in  the  table  are  to  be 
understood  as  approximations,  suitable,  however,  for  the  rough 
nature  of  such  measurements  as  are  here  descibed: 

Table  No.  2. — Discharge  of  Weirs  1  Foot  Long. 

Depth,  ft 0.4  0.45  0.5  0.55  0.6  0.65 

Discharge  . . , . . .  0.836  0.998  1.167  1.345  1.531  1.724 

Depth,  ft 0.7  0.75  0.8  0.85  0.9  0.95 

Discharge 1.925  2.133  2.347  2.568  2.795  3.028 

Depth,  ft 1.0  1.05  1.1  1.15  1.2  1.25 

Discharge 3.267  3.511  3.761  4.016  4.277  4.542 

Depth,  ft 1.3  1.35  1.4  1.45  1.5  1.55 

Discharge 4.812  5.087  5.367  5.051  5.940  6.233 

Depth,  ft 1.6  1.65  1.7  1.75  1.8  1.85 

Discharge 6.530  6.832  7.137  7.447  7.760  8.077 

Depth,  ft 1.9  1.95  2.0 

Discharge 8.398  8.723  9.051 

The  quality  of  water  from  a  watershed  depends  upon  the  popu- 
lation of  the  area,  the  number  of  swamps  in  it,  and  the  nature  of 
the  rock  formation  over  which  the  water  passes.  If  limestone  is 
common,  the  water  is  liable  to  be  too  hard,  if  there  are  swamps  on 
the  catchment  area,  the  color  is  apt  to  be  dark,  and  if  the  popu- 
lation on  the  watershed  is  more  than  about  300  per  square  mile, 
the  stored  water  often  proves  troublesome  from  bad  tastes  and 
odors.  "Shallow  storage  reservoirs,  from  which  the  soil  and  vege- 
table matter  have  not  been  removed,  generally  give  trouble,  and 
the  large  and  deep  reservoirs  of  the  same  character  are  by  no 
means  exempt/' 

The  suitability  of  water  for  a  town  and  municipal  supply  de- 
pends upon  its  freedom  from  sewage  contamination,  hardness, 


WATER-WORKS    MANUAL.  19 

color,  odor,  and  taste.  The  direct  sewage  contamination  of  a  sur- 
face supply  rarely  needs  to  be  determined  by  analysis,  as  the  in- 
spection of  the  watershed  will  indicate  any  sources  of  pollution. 
Where  water  is  drawn  from  lakes  and  streams  the  aid  of  the  chem- 
ist and  biologist  must  be  sought  before  judgment  can  be  passed 
safely  on  any  water.  These  analysts  have  generally  printed  direc- 
tions as  to  the  methods  by  which  samples  are  to  be  collected,  so 
it  is  hardly  necessary  to  give  such  instructions  here.  In  sending 
the  samples  full  information  should  be  furnished  regarding  the 
nature  of  the  surroundings  of  the  places  where  they  were  ob- 
tained, as  the  analyst  is  thereby  enabled  to  come  to  more  definite 
conclusions  regarding  the  availability  of  the  source  for  the  pur- 
poses proposed. 

Few  water  commissioners  and  superintendents  are  not  confront- 
ed sooner  or  later  with  apparently  formidable  tables  of  chemical 
analyses,  so  it  may  be  well  to  point  out  what  such  analyses  mean 
The  source  of  the  most  serious  pollution  of  water  is  organic  mat- 
ter. This  may  be  present  as  living  organisms  and  the  product  of 
organic  life,  or  the  matter  may  be  present  in  various  stages  of  de- 
composition. It  is  customary  to  classify  the  condition  of  the  or- 
ganic matter  by  means  of  the  condition  of  the  nitrogenous 'organic 
matter.  In  this  way  the  albuminoid  ammonia  is  taken  as 
an  indication  of  the  amount  of  undecomposed  organic  mat- 
ter. When  decomposition  has  begun,  its  extent  is  indicated  by 
the  presence  of  so-called  free  ammonia.  Further  changes  result 
in  altering  the  free  ammonia  to  nitrites,  which  finally  become  ni- 
trates, the  last  stage  in  the  process  of  alteration  by  which  organic 
matter  is  converted  into  a  form  suited  for  assimilation  into  new 
organic  matter.  It  is  imprudent  to  state  that  because  a  water  con- 
tains unusually  large  amounts  of  any  of  these  compounds  of  nitro- 
gen that  it  is  necessarily  polluted.  The  signification  of  each  com- 
pound may  be  stated  briefly  as  follows,  it  being  understood  that 
only  surface  waters  are  now  under  consideration: 

Albuminoid  ammonia  was  formerly  considered  as  an  indication 
of  the  presence  of  an  equivalent  amount  of  organic  matter  liable 
to  decay,  but  within  recent  years  it  has  been  found  that  this  it  not 
necessarily  so.  The  lesson  to  be  learned  from  this  compound  is 
indicated  most  clearly  by  successive  analyses  of  a  water,  for  if  the 
albuminoid  ammonia  remains  unchanged  for  months  without  de- 
veloping free  ammonia,  a  comparatively  large  amount  may  be 


20  WATER-WORKS.  MANUAL. 

harmless.  This  is  especially  the  case  with  brown  coloring  matter 
which  water  dissolves  from  grasses,  leaves  and  roots,  according  to 
Dr.  T.  M.  Drown,  who  instances  the  very  dark  water  of  Acushnet 
River,  the  source  of  New  Bedford's  supply,  as  a  good  water  con- 
taining enough  albuminoid  ammonia  to  be  classed  as  polluted  by 
most  European  standards. 

Free  ammonia,  so-called,  is  a  characteristic  ingredient  of  sew- 
age, but  "the  conditions  which  influence  its  development  and  ac- 
cumulation in  natural  waters  are  so  various  that  one  must  be  ex- 
tremely cautious  in  deciding  what  is  the  signification  of  its  pres- 
ence in  individual  cases."  If  an  analysis  shows  a  large  amount  of 
free  ammonia  in  a  water  from  a  catchment  area  having  dwellings 
upon  it,  further  investigations  should  be  made  into  the  causes  of 
its  presence. 

Nitrites  are  compounds  of  much  interest,  as  their  amount  is  gen- 
erally found  to  vary  less  with  the  seasons  than  the  other  organic 
derivatives,  and  they  are  therefore  a  better  index  of  sewage  pollu- 
tion. "High  free  ammonia  and  high  nitrites  together  are  charac- 
teristic of  recent  pollution,  and  when  they  are  uniformly  high  in 
a  surface  water  they  point  to  continuous  pollution." 

oSJitrates  indicate  the  complete  change  of  organic  to  inorganic 
matter,  and  their  importance  can  only  be  settled  satisfactorily 
when  the  source  from  which  they  were  derived  is  known.  The 
organic  matter  that  is  discharged  into  a  water  is  rarely  dangerous 
if  it  is  given  time  to  change  to  nitrates,  but  the  disease  germs  that 
may  have  been  discharged  at  the  same  time  may  be  still  a  source 
of  danger  when  the  chemical  changes  are  over.  Chemical  analy- 
sis, by  indicating  the  amount  of  albuminoid  and  free  ammonia, 
nitrites  and  nitrates,  points  out  the  probability  of  such  germs 
being  in  the  water  and  the  time  that  has  elapsed  since  they  were 
discharged  into  it.  The  time  is  probably  least  when  the  albumin- 
oid ammonia  is  high,  and  greatest  when  the  nitrates  are  high  in 
the  analysis. 

Chlorine  is  a  valuable  indication  of  sewage  contamination.  The 
amount  to  be  found  in  unpolluted  water  varies  widely;  in  Massa- 
chusetts it  decreases  as  the  distance  from  the  seashore  increases, 
and  it  is  highly  desirable  to  know  what  is  the  normal  amount  in 
unpolluted  water  in  a  given  region  before  deciding  upon  the  sig- 
nification of  the  amount  shown  by  analyses  of  samples  of  water 
of  unknown  character  from  the  same  locality.  The  chlorine  in 


WATER-WORKS    MANUAL. 


21 


the  reservoirs  of  the  Boston  water  system  is  found  to  vary  directly 
with  the  population  upon  their  respective  watersheds.  High  free 
ammonia,  high  nitrites,  and  high  chlorine  are  considered  to  af- 
ford complete  proof  of  pollution  by  sewage.  Dr.  Drown  has 
pointed  out,  however,  that  when  the  chlorine  is  not  much  above 
the  normal  in  waters  containing  high  free  ammonia  and  nitrites 
the  inference  is  that  the  pollution  comes  from  farmyards  or 
manured  fields,  a  distinction  that  it  is  often  important  to  make. 

Table  No.  3,  giving  a  number  of  analyses  of  waters,  shows  what 
is  meant  by  high  and  low  amounts  of  the  various  compounds  re- 
ferred to.  It  is  taken  from  the  Twenty-second  Annual  Report  of 
the  Massachusetts  State  Board  of  Health,  and  the  figures  stand  for 
parts  per  100,000.  The  first  six  analyses  are  of  unpolluted  waters, 
while  the  last  five  are  of  polluted  waters. 

Table  No.  3.— Water  Analyses. 
Free        Albuminoid 


Ammonia. 

Ammonia. 

Nitrates. 

Nitrites. 

Chlorine. 

1  ..... 

......     0.0000 

0.0022 

0.0060 

0.0000 

0.08 

2    

0.0702 

0.0030 

0.0030 

0.0006 

0.10 

3   

0.0000 

0.1252 

0.000.0 

0.0000 

0.10 

4   

0.0130 

0.0333 

0.0250 

0.0001 

0.16 

5   

0.0000 

0.0136 

0.0050 

0.0000 

0.63 

6   

0.0000 

0.0152 

0.0060 

0.0001 

2.10 

7   ..... 

0.0124 

0.0284 

0.0130 

0.0000 

0.19 

8   ..... 

0.0000 

0.0196 

0.0550 

0.0004 

0.54 

9   ..... 

0.0016 

0.0198 

0.0200 

0.0004 

0.58 

10   ..... 

0.0000 

0.0262 

0.0170 

0.0010 

2.09 

11  

0.0664 

0.0263 

0.0800 

0.0025 

2.41 

The  hardness  of  water  is  expressed  in  the  analyses  of  the  Massa- 
chusetts State  Board  of  Health  by  comparing  it  to  the  amount  of 
carbonate  of  lime  that  would  have  the  same  effect  in  an  otherwise 
pure  sample.  A  hardness  of  2  means  that  the  effect  of  the  soap 
curdling  substances  in  the  sample  would  be  produced  by  water 
containing  2  parts  per  100,000  of  carbonate  of  lime.  This  prop- 
erty has  little  hygienic  signification,  but  it  is  important  in  other 
respects,  for  if  the  substances  causing  it  are  present  in  large 
amounts  the  water  causes  trouble  in  steam  boilers.  Frequent  ref- 
erence is  made  in  reports  and  books  on  water  supply  to  Dr.  Clark's 
scale  of  hardness.  In  this  scale  each  degree  represents  the  hard- 
ness of  water  containing  the  equivalent  of  one  grain  of  carbonate 
of  lime  to  the  imperial  gallon;  22  degrees  of  hardness  is  therefore 
that  of  an  imperial  gallon  of  water  containing  soap-curdling  mat- 
ter producing  the  same  effect  in  it  as  would  22  grains  of  lime. 
Waters  of  more  than  5  degrees  of  this  scale  are  usually  considered 


22  WATER-WORKS    MANUAL. 

hard.  Chemists  distinguish  between  permanent  and  temporary 
hardness,  the  latter  being  the  amount  or  number  of  degrees  that 
may  be  removed  by  boiling.  A  water  temporarily  hard  will  give  a 
sludge  or  mud  in  a  boiler,  which  is  easily  cleaned  out,  while  one 
permanently  hard  will  produce  the  hard  scale  which  boiler-tenders 
find  so  difficult  to  remove. 

The  chemist  who  makes  an  analysis  of  water  should  always  be 
requested  to  supply  an  interpretation  of  it  so  that  the  results  of 
his  work  may  be  understood  by  persons  without  chemical  training. 
If  his  report  is  properly  prepared  the  foregoing  hints  will  prob- 
ably enable  its  significance  to  be  understood  readily.  The  reports 
of  bacteriological  analyses  should  always  be  accompanied  by  a 
statement  as  to  what  they  go  to  prove,  as  bacteriology  is  a  science 
of  such  rapid  progress  to-day  that  only  a  specialist's  interpretation 
of  an  analvsis  is  of  much  value- 


CHAPTER  II.— EARTH  DAMS. 

An  impounding  reservoir  is  often  regarded  as  nothing  but  an 
artificial  lake,  to  be  formed  in  the  cheapest  possible  manner,  but 
if  the  water  is  to  be  used  for  domestic  purposes,  such  a  view  will 
be  liable  to  lead  to  trouble.  The  dam  itself,  if  poorly  designed  or 
built,  may  be  a  source  of  danger  to  people  living  below  it;  if  it  is 
not  carried  into  the  underlying  strata  and  into  the  banks  so  as  to 
prevent  leakage,  considerable  water  may  be  lost;  if  the  surface  soil 
is  allowed  to  remain,  the  quality  of  the  water  may  be  very  bad  at 
times;  if  there  are  places  along  the  borders  of  the  reservoir  where 
the  depth  of  water  is  shallow,  weeds  may  grow  and  injure  the 
quality  of  the  water  when  they  decay;  if  the  reservoir  is  so  located 
that  the  disposition  of  the  strata  under  and  around  it  is  unfavor- 
able, the  water  may  leak  out  and  the  reservoir  prove  little  better 
than  a  strainer,  provided  the  bottom  is  not  made  tight  in  some 
way.  These  are  all  important  matters  to  be  settled  before  begin- 
ning work,  and  the  history  of  water-works  construction  in  this 
country  shows  that  much  money  has  been  wasted  and  much  an- 
noyance caused  by  failure  to  take  them  into  consideration. 

Fairly  water-tight  dams  can  be  made  of  many  materials  which 
are  unsuited  for  use  in  reservoir  embankments.  A  manufacturing 
canal  at  Nashua,  N.  H.,  has  a  bank  composed  of  nothing  but  pure 
sand,  through  which  in  its  natural  condition  water  passes  freely. 
In  the  60  years  this  canal  has  been  in  service  the  sand  has  become 
silted  with  fine  material  deposited  from  the  water,  and  it  is  now 
practically  tight.  The  old  Middlesex  Canal  in  Massachusetts  had 
banks  of  loose  gravel  which  must  have  allowed  large  quantities  of 
water  to  pass  early  in  its  history,  but  the  sediment  in  the  water 
filled  the  interstices  and  finally  made  the  banks  tight.  Reservoir 
embankments  of  sand  are  not  uncommon  in  India,  and  the  con- 
struction of  one  of  the  best  of  these  is  described  very  fully  in  the 
"Proceedings"  of  the  Institution  of  Civil  Engineers,  Volume  cxv., 
by  Col.  S.  S.  Jacob.  According  to  Mr.  Albert  F.  Noyes,  M.  Am. 


24  WATER-WORKS    MANUAL. 

Soc.  C.  E.,  a  reservoir  embankment  about  16  feet  high  has  been 
built  of  fine  sand,  the  slopes  being  1|  to  1  and  covered  with  the 
turf  taken  from  the  ground.  There  was  no  appreciable  leakage  of 
water.  A  section  of  the  bank  was  finally  carried  away,  the  break 
being  caused  by  a  woodchuck  hole.  It  was  repaired  by  filling  in 
the  opening  with  the  same  kind  of  material  that  was  washed  away, 
and  then  facing  the  inside  slope  with  hardpan,  a  kind  of  clay 
gravel,  put  on  in  thin  layers  until  a  total  thickness  of  2  feet  was 
obtained.  All  stones  above  2  inches  in  diameter  were  picked  out 
carefully,  and  the  layers  were  compacted  by  spading  rather  than 
by  rolling  or  tamping.  This  facing  was  covered  with  4  inches  of 
broken  stone  and  a  layer  of  riprap  12  to  14  inches  thick,,  It  was 
found  best  in  making  such  an  embankment  to  have  the  material 
slightly  damp  but  not  wet,  and  to  use  no  water  while  rolling  the 
layers.  In  spite  of  the  favorable  experience  with  some  dams  made 
of  sand,  it  cannot  be  regarded  as  a  material  suitable  for  such 
works,  when  anything  better  can  be  secured  at  a  not  prohibitory 
cost. 

When  it  comes  to  considering  the  other  varieties  of  earth  used 
for  embankments,  there  is  a  very  troublesome  obstacle  to  collect- 
ing information — viz.,  the  lack  of  uniformity  in  the  use  of  the 
terms  applied  to  the  various  materials.  There  are  a  few  rule-of- 
thumb  practices  regarding  earth  in  which  technical  terms  are  not 
involved,  among  them  is  one  adopted  in  the  neighborhood  of 
Lowell,  and  described  by  Mr.  Clemens  Herschel,  M.  Am.  Soc.  C* 
E.  There  the  fitness  of  a  material  for  puddling,  or  making  a 
water-tight  coating  or  layer,  was  ordinarily,  tested  by  placing  in  a 
pail  of  water  enough  of  it  to  render  the  water  invisible.  The  pail 
was  then  turned  upside  down,  and  if  the  mixture  dropped  out  it 
was  rejected;  if  it  remained  in  the  pail  it  was  considered  satisfao 
tory  for  puddling. 

The  importance  of  a  proper  selection  of  material  for  an  em- 
bankment is  so  great  that  a  number  of  opinions  of  leading  Amer- 
ican engineers  are  quoted  verbatim  below.  The  author  believes 
that  these  opinions  are  of  great  practical  value,  and  to  make  them 
as  useful  as  possible  they  are  classed  under  the  general  heads  of 
clay,  gravel,  and  mixtures. 

CLAY. 

"A  good  illustration  of  the  behavior  of  clay  when  used  for  pud- 
dling material  in  such  proportions  that  its  removal  from  the  mass 


WATER-WORKS    MANUAL.  25 

by  water  very  seriously  disintegrates  the  whole  mass,  occurred  on 
the  Ridgewood  reservoir  of  the  Brooklyn  Water-Works,  built  in 
1857-60.  The  reservoir  and  embankment  were  built  of  material 
taken  from  the  excavation,  and  well  rolled  and  rammed.  This 
material  was  the  Long  Island  drift.  Where  the  reservoir  was  ex- 
cavated below  the  natural  surface  of  the  ground  the  banks  were 
dressed  to  a  slope  of  1|  to  1,  and  a  puddle  facing  18  inches  thick  at 
right  angles  to  the  slope  was  put  on,  consisting  of  clay  and  grav- 
elly earth  in  about  equal  proportions.  This  material  was  wet  and 
cut  with  spades.  Above  the  natural  surface  the  puddle  wall  was 
carried  over  the  natural  surface  to  the  center  of  the  embankment, 
and  then  carried  up  vertically  in  the  center  of  the  embankment. 
These  banks  were  faced  with  a  slope  wall  of  split  boulders  about 
12  inches  thick,  with  the  interstices  well  filled  with  pinners. 
When  the  reservoir  was  filled  the  water  dissolved  the  clay  out  of 
the  puddle,  and  the  slope  wall  slid  in  some  cases  and  settled  back 
in  others,  and  it  was  necessary  to  empty  the  reservoir  and  relay 
the  whole  of  the  wall  in  cement  mortar.  Since  that  time  I  have 
never  attempted  to  use  clay  in  puddling  to  which  water  could  find 
access,  and  I  think  in  general  the  less  of  such  material  there  is 
used  in  puddling  a  wall  the  better  the  wall  is/' — J.  J.  R.  Croes,  M. 
Am.  Soc.  C.  E. 

"The  particles  of  clay  are  cohesive,  and  a  vein  of  water  ever  so 
small  which  finds  a  passage  under  or  through  clay  is  continually 
wearing  a  larger  opening.  An  embankment  of  clay  is  much  tight- 
er at  first  (than  one  of  gravel)  but  is  always  liable  to  breakage." — 
William  J.  McAlpine,  Past  President  Am.  Soc.  C.  E. 

"Clay  becomes  slimy  and  sticky  when  wet,  and  yet  it  is  difficult 
to  mix  it  thoroughly  with  water.  Hence  voids  are  apt  to  occur  in 
the  body  of  the  puddled  mass.  As  the  water  leaves  it  it  shrinks 
and  cracks,  and  yet  retains  water  in  parts;  so  that  it  never  prop- 
erly settles  down  and  becomes  compact,  but  is  liable  to  be  cut  away 
if  only  a  small  stream  of  water  passes  through  it,  or  if  it  is  placed 
in  water  which  is  only  gently  agitated.  I  have  no  doubt  that  clay 
owes  its  reputation  in  this  country  to  its  mention  in  accounts  of 
English  work.  There  is  a  vast  amount  of  what  farmers  call  in- 
and-in-breeding'  in  the  education  and  training  of  water-works  en- 
gineers in  the  United  States;  so  that  when  an  error  of  this  sort  is 
once  engrafted  it  is  not  easily  eradicated. — Clemens  Herschel,  M. 
Am.  Soc.  C.  E. 


26  WATER-WORKS    MANUAL. 

"Some  clays  are  apt  to  become  saturated  with  water  and  under 
certain  conditions  to  become  fissured.  They  cannot,  therefore,  be 
used  alone.  Moreover,  unless  a  clay  is  exceptionally  tough,  an 
aperture  through  it,  however  minute,  is  apt  to  become  enlarged 
and  finally  to  cause  serious  trouble.  We  find,  however,  that  a 
number  of  dams  of  great  height  are  reported  from  California  as 
being  built  of  clay.  The  designer  of  several  of  these  dams  stated 
that  he  had  subjected  a  cubic  foot  of  the  clay  to  a  hydraulic  pres- 
sure much  superior  to  that  corresponding  to  the  expected  depth  of 
water  behind  it  and  had  been  unable  to  force  water  through  it; 
but  these  clays  must  be  of  very  exceptional  quality." — A.  Fteley, 
M.  Am.  Soc.  C.  E. 

"Fat  or  unctuous  clays  are  mostly  designated  by  writers  on 
hydraulics  as  the  only  proper  material  of  which  to  form  an  im- 
pervious, water-tight  wall  in  the  heart  of  an  embankment,  or  the 
entire  mound  of  a  reservoir,  as  the  case  may  be;  and  yet  I  am  con- 
vinced that  more  failures  of  reservoir  embankments  and  of  high 
earth  dams  are  due  to  the  too  free  use  of  pure  clay  in  puddled 
core  walls,  and  to  the  almost  entire  dependence  placed  upon  such 
walls,  than  to  any  other  cause.  The  mistake  too  often  made  by 
engineers  is  that  of  supposing  that  only  clay  can  be  used  for  pud- 
dling. An  embankment  built  entirely  of  clay  is  an  unsafe  one, 
even  when  puddled  in  the  very  best  manner  possible.  It  is  easily 
attacked  by  muskrats  and  by  other  foes  of  a  water-tight  embank- 
ment/'—E.  F.  Smith,  M.  Am.  Soc.  C.  E. 

GRAVEL. 

"At  many  places  the  word  gravel  is  understood  to  mean  a  mass 
of  rounded  stone  of  varying  sizes.  This  sort  of  gravel  occurs  in 
very  large  deposits  in  many  places  and  it  is  similar  in  the  form  of 
its  constituent  parts  to  the  gravel  of  the  seashore.  The  other  sort 
of  gravel  is  made  up  of  stone  not  rounded,  but  rather  of  flat  shape, 
and  with  many  particles  of  very  small  size,  but  still  not  rounded. 
It  is  with  this  latter  sort  of  gravel  that  tight  puddle  can  be  made 
without  the  admixture  of  clay.  The  gravel  composed  entirely  of 
rounded  pebbles  of  varying  sizes  will  not  alone  make  a  tight  bank, 
\)\it  in  many  cases  where  clay  occurs  and  only  this  sort  of  gravel 
can  be  found,  an  excellent  puddle  is  made  by  a  suitable  mixture  of 
the  two.  This  is  the  case  in  the  banks  of  the  canals  of  the  State  of 


WATER-WORKS    MANUAL.  27 

Xew  York,  at  many  points  in  which  a  section  of  such  puddled 
material  is  formed  in  the  center  of  the  bank,  and  which,  when  cut 
into  afterwards,  is  found  to  be  compact  and  impervious/7 — John 
Bogart,  M.  Am.  Soc.  C.  E. 

"By  the  term  gravel  is  not  meant  a  collection  of  clean,  round, 
water- washed  pebbles  of  nearly  uniform  size,  but  a  combination  of 
small  stones,  sand,  and  loam  so  proportioned  that  all  interstices 
between  the  stones  will  be  thoroughly  rilled  by  finer  materials.  In 
certain  proportions  clay  is  valuable  in  such  a  mass,  provided  that 
it  is  so  situated  that  water  cannot  get  at  it  so  as  to  wash  out  the 
clay,  which  consists  of  very  fine  particles  capable  of  being  washed 
away  by  the  action  of  running  water." — J.  J.  R.  Croes,  M.  Am. 
Soc.  C.  E. 

"The  particles  of  fine  gravel  have  no  cohesion.  A  vein  of  water 
first  washes  out  from  the  gravel  the  fine  particles  of  sand,  and  the 
larger  particles  fall  into  the  space,  and  these  small  stones  first  in- 
tercept the  coarser  sand  and  next  the  particles  of  loam  which  are 
drifted  in  by  the  current  of  water, and  thus  the  whole  mass  puddles 
itself  better  than  the  engineer  could  do  with  his  own  hands.  The 
vacuities  produced  below  by  this  operation  are  indicated  by  the 
settlement  at  the  top,  where  more  gravel,  etc.,  can  be  added  as  is 
found  necessary.  An  embankment  of  gravel  is  comparatively  safe 
and  becomes  tighter  every  day." — William  J,  Me  Alpine,  Past 
President  Am.  Soc.  C.  E. 

"Gravel  capable  of  being  puddled  will  do  anything  that  clay 
was  ever  used  for  in  water-works  practice,  and  will  do  it  better.  I 
have  known  cases  where  clay  was  brought  at  considerable  expense 
to  a  bridge  site  to  be  filled  into  bags  and  used  in  coffer-dams,  while 
good  gravel,  which  would  have  done  the  work  much  better, 
abounded  close  at  hand.  Clay  placed  in  such  bags  washes  out  and 
disappears,  while  gravel  retains  nearly  its  full  dimensions  in 
water." — Clemens  Herschel,  M.  Am.  Soc.  C.  E. 

"Gravel  suitable  for  use  as  a  reservoir  embankment  may  be  de- 
fined as  a  material  resulting  from  the  disintegration  of  any  of  the 
harder  rocks,  with  the  admixture  of  water- washed  pebbles  and 
stones  not  larger  than  pigeon  eggs  nor  smaller  than  the  grains  of 
coarse  sand,  with  sufficient  clay  to  bind  the  mass  together  when 
compressed.  The  presence  of  a  suitable  binder  in  the  form  of 
clay  is  the  one  important  element  in  the  make-up  of  gravel  suit- 
able for  puddling."— E.  F.  Smith,  M.  Am.  Soc.  C.  E. 


28  WATER-WORKS    MANUAL. 

MIXTURES. 

"The  material  in  this  section  (Pittsburg,  Pa.)  contains  more 
clay  than  does  that  found  in  Massachusetts,  and  when  it  is  ex- 
cavated after  a  long  dry  spell,  it  is  apt  to  come  up  in  large  lumps. 
If  placed  on  the  hanks  in  thin  layers  in  its  natural  condition  and 
thoroughly  rolled  so  as  to  pulverize  the  lumps,  the  absorption  of 
"water  upon  the  filling  of  the  reservoir  causes  the  material  to  swell, 
and  in  my  opinion,  to  make  a  tighter  bank  than  when  the  material 
is  put  in  wet." — James  H.  Harlow,  M.  Am.  Soc.  C.  E. 

"The  writer  is  of  the  opinion  that  clay,  on  account  of  the  fine- 
ness of  its  particles  and  of  what  is  commonly  called  its  binding 
qualities,  must  enter  into  the  composition  of  the  material  used. 
That  a  very  small  proportion  of  it  is  sufficient  is  shown  by  the 
very  excellent  behavior  of  banks  wholly  formed  of  hardpan,  in 
which  the  gravel  and  fine  sand  are  cemented  by  the  admixture  of 
various  proportions  of  clay." — Alphonse  Fteley,  M.  Am.  Soc. 
C.  E. 

"When  engineers  appreciate  the  fact  that  a  homogeneous  bank  of 
gravel,  compacted  by  a  little  clay,  is  better  than  a  clay  core  with 
indifferent  material  on  both  sides  of  it,  the  number  of  failures  will 
be  comparatively  few.  Where  true  clays  are  used  in  proper  pro- 
portions with  other  material  they  are  fitted  for  the  purpose  of  res- 
ervoir construction.  In  this  I  do  not  include  those  so-called  clays 
which  originate  from  sand  that  has  been  reduced  to  finely  round- 
ed grains  and  which  rather  resemble  quicksand." — E.  F. -Smith, 
M.  Am.  Soc.  C.  E. 

"The  best  natural  puddle  we  have  is  hardpan,  and  if  any  of  you 
have  worked  in  hardpan  you  will  have  noticed  that  a  great  deal 
of  gravel  is  encountered  in  it;  it  is  also  pretty  hard  to  work,  while 
pure  clay  can  be  easily  worked.  My  experience  has  led  me  to  work 
about  3  to  1 — that  is,  I  take  pure  clay,  cut  it  up,  and  to  every 
three  barrows  of  it  dumped  down  an  embankment,  or  anything  of 
that  kind,  I  dump  down  a  barrow  of  gravel  and  sand." — Robert 
j  Cartwright,  M.  Am.  Soc.  C.  E. 

These  quotations  furnish  such  explicit  information  on  the  sub- 
ject of  earths  that  little  further  comment  is  necessary.  It  is  fre- 
quently desirable  to  form  artificial  mixtures  of  various  materials 
in  order  to  make  certain  portions  of  a  dam  particularly  tight. 
The  experienced  engineer  can  generally  decide  upon  the  proper 
proportions  without  recourse  to  trial,  but  in  case  experiments  are 


WATER-WORKS    MANUAL.  29 

necessary,  the  method  recommended  by  Col.  John  T.  Fanning,  M. 
Am.  Soc.  C.  E.,  is  probably  as  expeditious  and  satisfactory  as  any. 
It  consists  in  filling  a  water-tight  box  with  the  coarsest  material 
available,  and  then  pouring  in  water  until  all  the  voids  are  filled. 
The  water  is  drawn  off  and  measured,  showing  the  amount  of 
empty  space  in  the  box.  Then  this  material  is  mixed  with  as 
much  of  the  next  finer  available  grade  as  it  is  possible  to  get  into 
the  box,  and  the  voids  measured  with  water  again.  When  this 
process  has  been  repeated  down  to  the  mixture  with  sand,  the 
voids  then  left  unfilled  are  to  be  filled  with  clay.  Colonel  Fanning 
states  that  if  such  an  experiment  is  begun  with  1  cubic  yard  of 
coarse  gravel,  and  the  mixing  of  the  materials  is  well  done,  0.28 
yard  of  fine  gravel,  0.08  yard  of  sand,  and  0.03  yard  of  clay  will 
make  a  mixture  having  voids  of  microscopic  dimensions.  As  a 
standard  for  practical  purposes  he  recommends  1  cubic  yard  of 
coarse  gravel,  0.33  yard  of  fine  gravel,  0.15  yard  of  sand,  and  0.2 
yard  of  clay. 

MASONRY  CORE  WALLS. 

There  is  probably  as  much  controversial  literature  on  the  sub- 
ject of  masonry  core  walls  in  the  center  of  dams  as  on  any  subject 
pertaining  to  water-works  construction,  but  it  certainly  is  true 
that  the  general  trend  of  opinion  is  in  favor  of  their  use  in  im- 
pounding dams.  When  properly  built  -they  undoubtedly  add  to 
the  safety  of  an  embankment.  Unfortunately  they  have  some- 
times been  poorly  built  and  badly  designed,  and  have  naturally 
proved  useless  or  worse.  It  has  been  stated  by  one  eminent  Amer- 
ican engineer  that  a  core  wall  of  one  dam  that  failed  was  built  of 
such  insufficient  dimensions  that  a  horizontal  section  formed  a 
convenient  paper-weight,  the  thickness  of  the  wall  being  6  inches. 
On  this  subject  the  opinions  of  a  number  of  prominent  engineers 
are  presented  in  the  following  quotations: 

"It  seems  to  me  that  a  core  wall  is  always  a  good  thing,  and 
that  in  almost  any  ordinary  case  it  is  worth  its  cost.  There  are 
cases,  of  course,  where  its  cost  would  be  prohibitive,  and  there 
are  cases  where  the  material  is  of  such  an  excellent  nature  that 
one  is  justified  in  getting  along  without  it.  But  I  will  confess  my- 
self to  having  a  very  strong  preference  for  a  core  wall,  both  as  a 
preventive  against  the  workings  of  muskrats  and  of  woodchucks 
and  as  a  means  of  making  the  embankment  tight;  and  also  as  a 
means  of  causing  the  destruction  of  the  embankment  to  take  place 


30  WATER-WORKS    MANUAL. 

gradually  in  case  the  water  does  penetrate  it." — John  E.  Freeman. 
M.  Am.  Soc.  C.  E. 

"As  I  said  before,  my  idea  of  an  ideal  reservoir  would  be  one  of 
solid  masonry,,  and  it  can  be  made  tight,  and  when  it  is  once  made 
tight  it  is  there  forever.  But  we  can't  always  afford  to  build  a  re- 
servoir of  solid  masonry,  and  the  next  thing  to  it  is  to  have  a  core 
wall  of  masonry,,  which  I  should  construct  every  time  when  I 
could  get  the  material/'— M.  M.  Tidd,  M.  Am.  Soc.  C.  E. 

"In  high  reservoir  embankments  of  the  fin  de  siecle  American 
pattern,  sheet  piling  is  replaced  by  a  core  wall  of  either  concrete  or 
masonry,  founded  upon  the  ledge  or  upon  some  other  trustworthy 
substratum  below  the  original  meadow  level,  and  extending  up  to 
the  full- water  level.  This  core  is  made  some  4  or  5  feet  thick  at 
the  top  and  at  the  bottom,  tapering  each  way  from  top  and  bottom 
to  a  thickness  of  7  or  8  feet  at  the  original  meadow  level.  I 
have  heard  these  core  walls  criticised  on  theoretic  grounds,  but  I 
know  of  no  valid  objection  to  them." — Clemens  Herschel,  M.  Am. 
Soc.  C.  E. 

"When  it  can  be  done  within  proper  limits  of  economical  con- 
struction, the  writer  prefers  to  secure  water-tightness  by  means  of 
an  impervious  wall  built  in  or  near  the  center  of  the  embankment 
and  continuously  connected  with  the  impervious  bottom 
or  extended  downwards  to  a  safe  depth.  There  is  no  ques- 
tion that  homogeneity  in  the  mass  of  an  embankment  is  very  de- 
sirable; but  the  writer,  with  some  experience  of  the  difficulty  of 
obtaining  perfect  work  at  all  times,  and  of  the  trifling  causes  that 
can  produce  a  leak  through  an  earth  embankment,  prefers  to  use 
a  masonry  wall  as  a  core.  If  a  small  defect  exists  in  the  core  wall, 
only  a  limited  amount  of  water  can  find  its  way  out.  I  do  not  see 
that  the  presence  of  a  masonry  core  wall  weakens  the  structure  in 
which  it  is  built,  for  the  tendency  of  the  earth  is  to  settle  against 
the  masonry.  At  any  rate,  I  have  failed  to  find,  in  all  the  cases  of 
accidents  which  have  come  to  my  knowledge,  any  that  were  due  to 
the  presence  of  a  core  wall.  The  cause  of  the  failure  was  invari- 
ably a  defect  in  design  or  in  construction." — Alphonse  Fteley,  M. 
Am.  Soc.  C.  E. 

"With  regard  to  the  construction  of  earthen  dams,  the  speaker 
stated  his  belief  that  an  impervious  core  wall  could  be  obtained  of 
other  materials  than  masonry  which  would  be  just  as  good;  it 
must  be  made  of  the  best  materials,  however,  and  well  placed. 


WATER-WORKS    MANUAL.  31 

Many  miles  of  embankments  and  dams  are  now  standing  in  the 
United  States  in  which  the  center  is  a  wall  of  puddled  earth  and 
clay,  combined  in  suitable  proportions  and  placed  properly,  and 
such  walls  are  as  impervious  as  any  of  masonry  can  be." — Discus- 
sion by  J.  J.  E.  Croes  in  "Transactions"  Am.  Soc.  C.  E. 

"The  speaker  did  not  wish  to  go  on  record  as  being  opposed  to 
a  masonry  core,  and  he  had  under  consideration  at  that  moment  a 
dam  in  which  he  was  strongly  inclined  to  put  one.  On  the  other 
hand,  he  regarded  such  a  core  as  an  extreme  precaution  for  the 
sake  of  safety.  If  he  had  just  the  material  wanted  and  was  cer- 
tain that  water  would  not  rise  to  the  top  of  the  dam  he  was  design- 
ing, he  might  be  willing  to  build  it  without  any  masonry  core,  al- 
though it  is  60  feet  high." — Discussion  by  John  Bogart  in  "Trans- 
actions" Am.  Soc.  C.  E. 

Where  the  masonry  core  wall  is  omitted,  and  the  material  of  the 
dam  is  not  exceptionally  water-tight,  it  is  necessary,  in  the  class  of 
dams  under  consideration,  to  make  a  core  of  puddled  earth  or  a 
facing  of  that  material  on  the  upstream  slope  of  the  embankment. 
In  most  cases  the  former  construction  is  preferable  for  the  reason 
stated  concisely  by  Mr.  Fitzgerald,  as  follows:  "For  the  same 
amount  of  money  more  puddle  can  be  put  in  a  vertical  wall  than 
on  a  slope  of  equal  height.  A  puddle  wall  in  the  center  of  a  bank 
is  not  exposed  to  the  danger  of  slipping  when  the  surface  of  the 
reservoir  is  suddenly  drawn  down.  The  water  does  not  seem  to 
work  out  of  the  puddle  (when  on  the  face  of  an  embankment) 
quickly  enough  to  drain  the  bank,  and  the  result  is  a  head,  which 
caves  the  slope.  Puddle  in  the  center  of  an  embankment  is  less 
exposed  to  frost,  to  drying  out  and  to  cracking  than  it  is  on  the 
slope."  The  puddle  earth  ought  to  be  of  the  best  quality,  free 
from  lumps,  without  any  stones  larger  than  2  inches,  and  prefer- 
ably still  smaller,  put  on  in  layers  not  exceeding  6  inches  in  thick- 
ness, and  cut  and  crosscut  with  spades  every  inch  or  so,  until  the 
layer  is  not  more  than  4-|-  or  5  inches  thick.  Where  the  puddle 
covers  such  an  area  that  grooved  rollers  can  be  employed  to  ad- 
vantage, it  may  be  used  in  4-inch  layers  and  compacted  in  the 
manner  to  be  described  under  the  head  of  methods  of  construc- 
tion. There  is  no  question  that  such  a  mass  of  puddle,  if  made  of 
small,  clean  gravel  with  some  clay,  will  be  practically  water-tight, 
but  it  cannot  be  relied  upon  to  stop  the  burrowing  of  muskrat0 
and  woodchucks,  which  only  masonry  will  prevent. 


32  WATER-WORKS    MANUAL. 

No  matter  what  material  is  employed  for  a  core  wall,  it  must  be 
carried  down  far  enough  and  deep  enough  into  the  sides  of  the 
valley  to  prevent  the  passage  of  water  under  or  around  the  dam 
through  the  undisturbed  natural  earth.  This  subject  will  be  dis- 
cussed later. 

WATER  IN  EARTHWORKS. 

The  tendency  to  use  too  much  water  in  consolidating 
the  layers  of  earth  in  an  embankment  is  perfectly  nat- 
ural from  a  contractor's  point  of  view,  because  the  liberal  use 
of  water  will  apparently  make  a  very  tight  bank  with  the  mini- 
mum expenditure  of  labor  and  time.  With  most  of  the  materials 
used  for  such  works,  however,  there  is  a  strong  probability  of 
chinking  of  the  bank  as  the  surplus  water  dries  out,  if  an  excessive 
amount  is  used.  Everyone  has  noticed  how  mud  flats  crack 
when  exposed  to  the  sun,  and  the  action  is  the  same,  though  on  a 
much  smaller  scale,  in  an  embankment  kept  too  wet  during  con- 
struction. An  experimental  proof  of  this  was  furnished  by  some 
investigations  made  by  Mr.  FitzGerald  in  connection  with  his 
studies  of  evaporation.  He  filled  eight  large  zinc-lined  tanks 
with  gravel,  sand,  earth,  and  mixtures  of  puddle  and  other  ma- 
terials. In  all  cases  where  the  filling  was  wet  it  was  found  to  be 
impossible  to  keep  the  tanks  full,  no  matter  how  much  ramming 
was  done.  By  ramming  in  dry  materials,  however,  no  trouble 
from  shrinkage  was  experienced,  and  in  every  case  the  material 
brought  the  paint  off  from  the  zinc  when  it  was  removed.  Some- 
times, as  in  the  case  of  the  reservoir  of  the  new  water-works  at  As- 
toria, Ore.,  the  earth  for  a  reservoir  embankment  is  found  in  such 
a  condition  that  no  watering  at  all  is  necessary.  With  hardpan, 
however,  some  water  must  be  used  to  make  a  compact  bank.  This 
material  breaks  up  in  lumps  about  3  to  6  inches  in  size,  which  it 
is  difficult  to  pulverize,  especially  if  hard.  If  a  little  water  is  used 
to  moisten  the  lumps,  and  the  moist  material  is  laid  in  courses  not 
over  4  inches  thick  and  well  rolled,  the  bank  can  be  made  very 
tight.  Dexter  Brackett  gives  the  cost  of  the  watering  and  rolling 
of  an  embankment  containing  80,000  cubic  yards  of  hardpan  as 
about  2  cents  a  cubic  yard,  the  work  being  done  thoroughly.  It 
is  particularly  important  to  have  the  rolling  and  ramming  of  the 
material  done  under  the  supervision  of  a  conscientious  inspector, 
where  but  little  watering  is  done,  as  the  work  is  apt  to  be  slighted. 
Alphonse  Fteley  advises  the  use  of  enough  water  "to  give  plas- 


WATER-WORKS    MANUAL.  35 

ticity  to  the  earth  and  to  moisten  it  to  about  the  same  degree  as  is 
observed  in  a  deep  excavation  free  from  water." 

In  the  construction  of  the  Clinton  and  Oak  Eidge  dams  of  the 
East  Jersey  Water- Works  the  gravel  composing  them  was  spread 
in  thinner  layers  than  usual,  not  over  4  inches  thick,  which  were 
reduced  to  about  2£  inches  after  rolling.  J.  Waldo  Smith,  M. 
Am.  Soc.  C.  E.,  reports  that  at  first  the  method  of  sprinkling  and 
then  rolling  was  followed.  It  was  found  that  better  work  could 
be  done  and  the  material  compacted  more  thoroughly  by  rolling 
first,  then  sprinkling  and  rolling  a  short  time,  and  giving  a  final 
wetting  just  before  the  next  layer  was  applied.  The  theory  on 
which  this  procedure  is  based  is  that  the  air  can  be  better  forced 
out  of  the  loose  gravel,  and  the  material  made  more  compact  while 
in  a  dry  or  naturally  moist  state,  and  that  the  subsequent  addition 
of  water  still  further  settles  and  binds  the  whole  mass.  Whatever 
merit  this  theory  may  have,  the  practice  it  leads  to,  the  use  of  a 
minimum  quantity  of  water,  agrees  with  the  best  usage  at  present. 

The  following  clause  is  taken  from  the  specifications  for  Ee- 
servoir  M  of  the  Croton  Water- Works  of  New  York  City: 

"Ample  means  shall  be  provided  for  watering  the  banks,  and 
any  portion  of  the  embankment  to  which  a  layer  is  being  applied 
shall  be  so  wet,  when  required,  that  water  will  stand  on  the  sur- 
face. The  contractor  shall  furnish  at  his  own  cost  the  necessary 
steam  or  other  power  for  forcing  the  water  upon  the  bank  if  the 
engineer  finds  that  other  means  of  transportation  and  distribution 
of  the  water  are  not  sufficient." 

The  specifications  for  the  dam  for  Eeservoir  No.  5  of  the  Bos- 
ton Water- Works  read  much  the  same  on  the  subject  of  watering. 
The  wording  of  the  clause  in  them  is  as  follows: 

"Ample  means  shall  be  provided  for  watering  the  banks,  and 
any  portion  of  the  embankment  to  which  a  layer  is  being  applied 
shall  be  so  wet,  when  required,  that  water  will  stand  on  the  sur- 
face. The  contractor  shall  furnish  at  his  own  cost  the  necessary 
steam-pumping  plant  and  force  main  for  forcing  water  into  a  tank 
situated  on  the  side  hill,  at  least  50  feet  above  the  top  of  the  dam 
when  completed.  From  this  tank  a  3-inch  distribution  pipe,  with 
gates  and  hose  connections,  will  lead  lengthwise  over  the  dam  to 
supply  water  wherever  it  may  be  needed.  If  the  engineer  ap- 
proves, some  other  method  of  equal  efficiency  for  the  furnishing 
of  water  may  be  substituted  for  the  above  plant." 


34  WATER-WORKS    MANUAL. 

These  clauses  refer  to  particular  pieces  of  work  very  carefully 
studied  by  Messrs.  Fteley  and  FitzGerald  respectively.  While 
they  might  be  considered  as  indicating  a  preference  for  heavy 
watering,  if  they  are  examined  carefully  in  connection  with  the 
previously  mentioned  statements  of  these  engineers,,  it  will  be  ap- 
parent that  they  are  intended  mainly  to  secure  provision  by  the 
contractor  of  ample  watering  facilities,,  in  case  they  should  be 
needed.  Like  all  other  clauses  from  specifications  which  are 
printed  in  this  series  of  articles,  they  are  to  be  regarded  as  sug- 
gestions only,  and  not  copied  verbatim.  It  would  be  very  foolish 
to  insert  the  Boston  clause  in  specifications  for  a  small  dam  to  be 
made  of  a  naturally  moist  mixture  of  gravel,  sand,  and  clay  which 
does  not  require  watering. 

CROSS-SECTION   OF   THE   EMBANKMENT. 

The  cross-section  given  the  dam  depends  somewhat  on 
its  height,  but  the  general  form  has  been  pretty  well 
standardized  by  this  time.  American  engineers  have 
learned  that  it  is  unnecessary  to  have  such  flat  slopes  as  are 
usually  adopted  abroad;  2  to  1  on  the  inner  face,  and  the  same 
rate, or  2J  to  1  on  the  outer  face,  are  the  slopes  generally  employed. 
If  the  dam  is  quite  high,  a  berm  5  or  6  feet  wide  should  be  made 
on  the  inner  face  a  few  feet  below  the  low-water  level,  and  a  wider 
berm  should  be  built  on  the  outer  face  about  one-third  to  one-half 
the  distance  from  the  top.  The  latter  was  probably  first  used  in 
this  country  by  Mr.  FitzGerald,  and  provides  a  means  of  longitu- 
dinal drainage  to  protect  the  loam  covering  of  the  slope  until  the 
grass  becomes  well  rooted  on  it.  This  berm  must  be  well  drained 
itself,  however,  or  water  will  pass  from  it  under  the  grass,  under- 
mining and  destroying,  it.  The  height  of  the  dam  above  the 
high-water  level  depends  somewhat  upon  the  size  of  the  structure. 
If  it  is  a  high  dam,  the  bank  should  rise  above  this  level  about  18 
inches  plus  the  depth  of  the  frost  in  the  locality  where  it  is  built. 
If  the  structure  is  low,  this  height  is  often  made  less  and  reliance 
placed  on  additional  width  at  the  top  to  prevent  frost  cracks  from 
opening  passages  for  the  passage  of  water.  Allowance  must  also 
be  made  for  the  height  of  waves  in  some  cases.  The  width  of  the 
dam  on  top  should  not  be  less  than  10  feet  unless  the  structure  is 
very  small.  All  angles  in  the  cross-section  as  first  sketched  out 
should  be  rounded  off,  as  angles  in  earthwork  are  entirely  theo- 
retical, except  in  rare  cases. 


WATER-WORKS    MANUAL.  35 

STARTING  THE  CORE   WALL. 

The  portion  of  the  dam  liable  to  give  the  most  trouble  is  the 
bottom  of  the  core  wall  or  the  puddle  core,  since  it  has  to  be 
carried  down  to  impervious  material  and  may  require  diffi- 
cult trenching  in  water  bearing  strata.  Quicksand  is  usually 
the  worst  material  to  deal  with,  and  in  case  it  is  encountered  the 
following  notes  may  prove  of  value.  They  are  abridged  from  a 
very  valuable  paper  on  the  method  in  which  a  breach  was  re- 
paired in  the  dam  of  the  storage  reservoir  of  the  Xew  Bedford 
Water- Works.  This  paper  was  written  for  the  American  Society 
of  Civil  Engineers  by  the  late  William  McAlpine. 

In  the  course  of  the  repairs,  a  trench  had  to  be  made  water- 
tight with  sheet  piling  exposed  in  places  to  a  head  of  more  than  20 
feet.  For  such  a  purpose  Mr.  McAlpine  considered  driven  sheet 
piling  worse  than  useless.  His  plan  was  to  excavate  the  trench  to 
the  greatest  depth  practicable,  and  to  place  in  the  bottom  a  hori- 
zontal timber  to  which  closely  jointed  planks  were  spiked.  These 
planks  were  spiked  to  a  similar  timber  at  the  top,  and  were  cov- 
ered by  a  second  course  of  jointed  boards.  A  water-tight  barrier 
can  be  made  in  this  way,  which  it  is  very  difficult,  if  not  imprac- 
ticable, to  obtain  with  driven  plank.  Another  point  to  be  con- 
sidered in  sheeting  a  trench  is  that  water  will  pass  horizontally 
and  vertically  along  a  smooth  surface  for  a  great  distance  until  it 
finds  open  joints  through  which  it  will  pass  freely.  Water  abhors 
angles,  and  by  compelling  it  to  make  a  sufficient  number,  its  head 
can  be  destroyed  entirely.  The  interposition  of  angles  is  often 
the  only  defense  the  engineer  has  against  water,  and  the  practice 
of  placing  instead  of  driving  sheet  piling  enables  many  of  these  to 
be  obtained.  There  are  three  rules  to  be  observed  in  excavating 
quicksand.  (1)  the  water  must  be  removed  promptly  and  thor- 
oughly, (2)  the  excavation  must  be  made  with  the  utmost  dis- 
patch, (3)  the  material  must  not  be  disturbed  after  it  begins  to 
quake.  Quicksand  is  a  mixture  of  fine  sand  with  such  a  propor- 
tion of  clay  or  loam  as  enables  the  mass  to  retain  water  within 
itself;  and  when  in  this  condition,  after  it  has  been  trampled  upon 
for  a  short  time,  it  begins  to  quake,  so  that  it  may  also  be  called 
quakesand.  When  it  reaches  this  condition,  if  it  is  left  quiet  for 
a  few  hours,  the  heavier  particles  of  sand  and  clay  settle  down  and 
expel  the  water,  and  the  mass  becomes  firm  again.  If,  on  the 


36  WATER-WORKS    MANUAL. 

other  hand,  it  is  further  disturbed  by  the  feet  of  the  workmen,  it 
becomes  more  and  more  fluid,  additional  material  flows  in  from 
the  sides,  and  no  progress  can  be  made  in  the  excavation.  When 
the  engineer  has  such  a  work  on  hand  he  should  provide  ample 
pumping  power,  and  in  most  cases  he  will  find  a  power  several 
times  as  great  as  he  anticipated  will  often  prove  most  economical 
in  the  end.  The  pumps  should  be  capable  of  lifting  sand  as  wel] 
as  water,  and  those  are  best  which  are  not  liable  to  be  clogged; 
this  is  of  more  consequence  than  that  they  should  work  with  a 
good  duty. 

Mr.  Me  Alpine  found  that  in  most  cases  sheet-piling  protections 
around  the  pit  to  prevent  the  influx  of  sand  are  useless  and  often 
detrimental.  If  there  is  room  to  allow  the  excavation  to  take  its 
natural  slope  and  the  three  rules  are  observed,  the  sheet-piling 
protection  will  be  found  unnecessary.  Quicksand  in  a  dry  state 
may  be  excavated  nearly  vertical. 

In  the  work  at  New  Bedford  the  dimensions  of  the  pit  on  top 
were  about  50  feet  width  by  100  feet  length.  There  were  30  la- 
borers employed.  Six  were  kept  constantly  at  work  removing  and 
casting  £side  the  sand  from  about  and  under  the  pump,  to  keep  it 
far  below  the  other  pa~ts  of  the  excavation.  Twelve  men  were 
employed  all  the  time  opening  small  ditches  radiating  from  the 
pump  pit.  Six  men  were  employed  in  excavating  the  ridges  left 
between  the  radiating  ditches,  and  as  long  as  the  latter  were  kept 
open  these  ridges  offered  perfectly  dry  digging.  The  remaining 
men  were  employed  in  casting  further  back  the  earth  which  was 
thrown  out  by  the  six  men  last  mentioned.  The  actual  removal 
of  the  earth  was  measured  by  the  work  of  only  six  men  out  of  30, 
but  these  six  had  perfectly  dry  earth  to  handle.  There  was  con- 
siderable difficulty  in  compelling  the  men  to  follow  the  rules  men- 
tioned previously.  They  were  violating  them  constantly,  al- 
though they  had  palpable  evidence  of  the  disastrous  results  due 
to  their  neglect. 

Work  was  begun  early  in  the  morning,  and  by  noon  the  pit  had 
been  sunk  to  a  depth  of  12  feet  at  the  lowest  place.  By  this  time 
it  was  apparent  that  the  extreme  capacity  of  the  pump  had  been 
reached,  and  it  became  impossible  to  keep  open  the  radiating 
ditches.  Consequently  the  earth  between  them  became  suffused, 
and  the  whole  of  the  lower  portion  was  transformed  from  hard 
compact  sand  into  a  semi-fluid  material  quaking  like  jelly.  Water 


WATER-WORKS    MANUAL.  37 

began  to  boil  up  in  many  places  in  the  bottom,  and  it  was  evident 
that  no  further  progress  could  be  made  at  this  time. 

The  method  of  carrying  on  the  work  was  then  changed.  It 
was  very  important  that  sheet  piling  should  be  placed  at  a  much 
greater  depth  than  the  excavation  had  been  carried,  but  Mr.  Mc- 
Alpine  believed  that  to  drive  the  plank  to  the  desired  depth  would 
have  resulted  in  open  joints  at  the  bottom.  It  was  therefore  de- 
termined to  lessen  the  number  of  such  joints  by  making  up  the 
plank  in  panels  of  4  feet  width,  with  their  joints  matched  and  bat- 
tened with  1-inch  boards.  One  of  these  panels  was  placed  in  the 
proper  line  of  the  sheet  piling,  and  forced  down  by  pressure  to  a 
depth  of  nearly  5  feet.  A  second  panel  was  forced  down  in  the 
same  manner  and  with  considerable  trouble  a  tolerably  close  joint 
was  made  with  the  first  and  further  secured  by  a  plank  driven  over 
the  joint.  Successive  panels  were  placed  in  this  manner  until  the 
pit  was  covered  by  two  rows  of  sheet  piling  placed  15  feet  apart. 
There  was  considerable  leakage  through  this  piling,  but  by  spend- 
ing about  $200  in  improving  the  sluice  by  which  the  water  in  the 
river  was  conducted  past  the  pit,  more  than  half  the  leakage  was 
prevented.  Under  the  new  conditions  the  pump  was  found  to 
have  ample  power  to  free  the  pit  from  water  and  enable  the  joints 
in  the  sheet  piling  to  be  calked  so  that  the  puddle  could  be  put  in. 

The  full  account  of  the  work  thus  carried  out  will  be  found  in 
Paper  No.  VII.  of  the  "Transactions"  of  the  American  Society  of 
Civil  Engineers.  It  is  one  of  the  most  helpful  articles  ever  writ- 
ten for  engineers  engaged  in  hydraulic  work,  and  is  fortunately 
still  in  print. 

Another  method  of  dealing  with  quicksand  which  has  proved 
very  satisfactory  in  many  places  consists  in  sinking  driven  wells 
along  both  sides  of  the  trench.  By  pumping  continually  from 
these  wells  the  subsurface  water  is  kept  at  a  low  level  in  the  vicin- 
ity of  the  construction.  An  illustrated  description  of  the  method 
followed  in  such  a  piece  of  work  on  the  Metropolitan  sewerage  sys- 
tem of  Boston  was  published  in  "The  Engineering  Kecord"  of 
January  21,  1893. 


CHAPTER  III.— MINOR  DETAILS  OF  RESERVOIRS. 

For  the  class  of  reservoirs  used  for  small  works  such  as  are  de- 
scribed in  these  articles,  the  construction  of  the  pipes,  gate-houses 
and  waste  weir  is  a  very  simple  matter.  But  two  pipes  will  be 
needed  in  the  great  majority  of  such  reservoirs,  one  for  the  regu- 
lar supply  and  the  other  -for  a  waste  pipe  through  which  to  draw 
off  the  impounded  water.  In  carrying  a  pipe  through  an  em- 
bankment subjected  to  water  pressure,  there  are  two  points  which 
must  always  be  kept  in  mind.  The  first  is  that  the  exterior  sur- 
face of  a  pipe  or  conduit  of  masonry  offers  excellent  opportunities 
for  leakage  of  water,  and  the  second  is  that  a  pipe  carried  through 
an  artificial  bank  is  always  exposed  to  breakage  by  the  settlement 
of  the  earth. 

Mr.  McAlpine's  famous  axiom,  "Water  abhors  an  angle,"  has 
already  been  mentioned,  but  it  may  be  repeated  again  here  as  indi- 
cating the  method  of  preventing  the  leakage  of  water  along  the 
pipes.  The  greatest  care  should  be  exercised  in  laying  the  pipes 
to  have  the  earth  tamped  firmly  against  them,  but  even  the  most 
painstaking  supervision  in  this  respect  will  fail  to  prevent  the 
passage  of  water  along  them.  Hence  cut-off  walls  of  concrete  or 
good  masonry  should  always  be  built  around  the  pipe  to  break  the 
uniformity  of  surface  and  prevent  the  percolation  of  water.  The 
late  M.  M.  Tidd  was  accustomed  to  have  cast  on  some  of  his  pipes 
to  be  laid  through  an  embankment,  a  collar  or  flange,  2  or  3  inches 
high  and  perhaps  2  inches  wide,  which  was  firmly  bedded  in  ce- 
ment. In  small  reservoir  dams  a  masonry  cut-off  placed  around 
the  pipe  midway  between  the  core  wall  and  the  foot  of  the  inner 
slope,  and  another  midway  between  the  core  wall  and  the  foot  of 
the  outer  slope,  will  be  sufficient  to  stop  any  leakage,  if  the  earth 
is  tamped  firmly  about  the  pipe.  These  blocks  of  masonry  should 
be  made  with  great  care,  and  if  they  stand  out  18  to  24  inches 
from  the  pipe  no  harm  will  be  done;  they  need  not  be  more  than 
18  to  24  inches  thick. 


WATER-WORKS    MANUAL.  39 

When  a  pipe  is  carried  through  an  embankment  it  ought  never 
to  be  supported  on  a  series  of  masonry  piers,  one  under  each  joint, 
as  this  practice  is  simply  an  urgent  invitation  to  troubles  of  vari- 
ous sorts.  In  case  the  embankment  settles,  every  length  of  pipe 
is  subjected  to  a  bending  stress  which  tends  to  cause  leaks.  The 
moment  a  leak  occurs,  the  water  under  pressure  enters  the  earth 
about  the  pipe  and  loosens  it,  arid  if  the  water  does  not  sooner  or 
later  pass  along  the  outside  of  the  pipe  to  the  face  of  the  dam  and 
cause  a  washout  of  part  of  the  structure,  it  will  be  more  a  matter 
of  good  luck  than  good  engineering.  The  fact  that  many  pipes 
supported  in  this  way  have  not  broken  does  not  make  the  practice 
a  good  one.  The  ideal  manner  of  carrying  a  pipe  through  a  dam  is 
by  resting  it  on  some  natural  foundation,  ledge,  or  dense  hardpan, 
which  is  known  to  be  absolutely  unyielding,  but  if  this  cannot  be 
done,  a  concrete  or  cement  masonry  wall,  with  several  projecting 
cut-offs  and  a  rough  surface,  ought  to  be  built  to  support  its  entire 
length.  The  dimensions  of  such  a  foundation  wall  depend,  of 
course,  on  the  local  conditions  of  each  problem. 

The  ideal  method  of  leading  pipes  from  a  reservoir  is  to  carry 
them  through  the  natural  foundations  at  one  side  of  the  embank- 
ment. This  is  generally  quite  expensive  arid  does  not  offer  many 
advantages  in  the  case  of  small  reservoirs,  although  where  the 
dams  are  high  this  plan  is  to  be  selected,  if  possible,  for  reasons 
which  it  is  unnecessary  to  explain  here. 

Too  much  emphasis  cannot  be  laid  on  the  importance,  in  any 
dam  having  pipes  laid  through  it,  of  preventing  the  percolation 
of  water  along  their  exterior  surface,  and  of  preventing  the  break- 
age of  the  pipes  by  settlement. 

GATE-HOUSES. 

The  gate-house  of  a  small  reservoir  is  a  very  simple  struc- 
ture. In  designing  it,  care  should  be  taken  that  it  is  firmly 
founded,  and  that  there  is  no  chance  for  the  pipes  from  it 
to  become  broken.  The  nature  of  the  foundation  is  naturally 
governed  by  local  conditions,  but  in  case  it  must  be  on  any  other 
material  than  rock  particular  care  must  be  paid  to  securing  an 
ample  bearing  area,  as  the  bottom  of  the  gate-house  and  its  con- 
nection with  the  dam  are  frequently  weak  points  in  an  otherwise 
good  design.  There  should  be  an  opening  in  the  wall  at  the  level 
of  the  bottom  of  the  gate  chamber  to  enable  the  water  to  be  drawn 


40  WATER-WORKS    MANUAL. 

off  to  the  bottom  of  the  reservoir,  and  it  is  a  good  plan  to  cover 
the  bottom  of  the  reservoir  with  riprap  in  front  of  the  entrance, 
if  this  can  be  done  without  much  expense.  The  other  openings 
for  water  may  be  from  6  to  8  feet  apart  vertically.  The  size  of 
the  openings  at  each  level  may  be  determined  by  means  of  the  fol- 
lowing formula:  A  =  0.3  Q,  where  A  is  the  area  in  square  inches 
and  Q  is  the  maximum  quantity  of  water  in  cubic  feet  per  second 
which  the  pipe  line  from  the  reservoir  will  carry. 

Manufacturers  of  valves  now  supply  sluice  gates  for  any  open- 
ings which  will  be  required  for  small  gate-houses.  They  have 
bronze  facing  on  the  seats  and  gate  faces,  and  can  be  had  with  a 
spigot  on  the  back  for  building  them  into  the  wall  or  with  flanges 
by  which  they  may  be  bolted  to  the  end  of  the  pipe.  The  gates 
are  raised  in  two  ways,  by  means  of  a  rising  stem  and  by  means  of 
a  non-rising  stem.  The  rising  stem  is  a  rod  firmly  attached  to 
the  gate  and  threaded  at  the  upper  end.  A  hand  wheel  bearing 
against  a  large  washer  or  plate  is  screwed  on  the  end  of  the  rod, 
and  by  turning  the  wheel  the  gate  is  manipulated.  The  non-ris- 
ing stem  has  a  thread  at  the  lower  end  and  is  keyed  to  the  hand- 
wheel.  The  gate  has  a  threaded  hole  through  which  the  lower 
end  of  the  rod  passes,  and  is  raised  and  lowered  by  turning  the 
rod  by  means  of  the  wheel.  The  rising  stem  is  cheaper  and  pref- 
erable in  most  cases.  The  face  of  the  sluice  opening  on  the  out- 
side of  the  gate-house  should  be  finished  off  smoothly  so  that  it 
may  be  closed  with  a  wooden  plug  wrapped  with  canvas  in  case  of 
an  emergency. 

The  gate  chamber  is  generally  built  of  rubble  or  brick  masonry, 
but  sometimes  other  materials  have  been  used.  Now  that  vitri- 
fied brick  are  so  cheap  the  best  lining  in  many  cases  would  be 
made  of  this  material,  but  good  hard-burned  brick  will  answer. 
In  fact  no  lining  at  all  will  be  needed  with  the  rubble  masonry  of 
some  parts  of  the  country,  as  a  really  good  Portland  cement  finish 
will  answer  all  purposes.  This  applies  to  small  work  only.  In 
the  design  of  the  gate-house  particular  care  should  be  paid  to  se- 
curing a  structure  which  will  not  be  exposed  to  damage  by  the  ice. 
During  the  winter  and  early  spring  there  is  always  a  possibility 
that  the  water  will  rise,  lifting  the  ice  and  loosening  that  portion 
between  the  gate-house  and  the  sloping  back  of  the  dam,  so  as  to 
bring  a  strong  pressun  against  the  former.  In  very  cold  climates 
there  is  also  dange  01  the  ice  lifting  the  masonry  if  the  latter  is 


WATER-WORKS    MANUAL.  41 

very  light.  For  these  reasons  a  gate-house  is  generally  a  more 
massive  structure  than  a  statical  analysis  of  the  strains  upon  it 
would  call  for. 

The  arrangement  of  the  effluent  pipes  from  a  small  reservoir 
admits  of  little  variety.  Two  different  plans  are  shown  in  Figures 
2  and  3,  and  modifications  of  these  will  probably  answer  all  pur- 
poses. The  first  plan,  shown  in  Figure  2,  will  answer  for  the 


i*- 16"-* 


Waste  Pipe, 


FIGURE  3. 


FIGURE  4. 


smallest  reservoirs.  The  waste  and  main  pipes  end  in  elbows, 
with  the  openings  flush  with  the  bottom  of  the  chamber,  and  have 
no  valves  at  the  inlet  end.  The  cut  is  a  section  through  one  of 
the  pipes.  In  case  it  is  desired  to  close  the  end  of  either  pipe,  it 
can  be  done  very  quickly  by  means  of  an  iron  plug  wrapped  with 
canvas,  a  little  hemp  being  placed  as  a  padding  between  the  can- 


42  WATER-WORKS    MANUAL. 

vas  and  iron.  The.  tightness  of  such  a  plug  is  surprising,  and  it 
can  be  placed  in  position  by  means  of  a  rope  or  chain  when  the 
well  is  full  of  water.  The  suction  of  the  water  entering  the  pipe 
will  seat  the  plug  firmly.  Above  the  mouths  of  the  pipes  is  a 
weighted  wooden  frame  having  a  screen  of  No.  10  copper  wire 
making  quarter-inch  meshes,  or  a  sheet  of  copper  perforated  with 
quarter-inch  holes  close  together.  The  copper  sheet  is  cleaned 
more  easily  than  the  screen.  The  frame  is  arranged  so  that  it  can 
be  lifted  to  the  surface  readily.  When  such  a  system  as  this  is 
employed  a  small  valve  chamber  should  be  built  at  the  outer  toe 
of  the  embankment  and  covered  with  a  strong  wooden  or  masonry 
box,  by  which  the  valves  may  be  reached.  The  cover  to  the  box 
should  be  provided  with  a  good  lock  to  prevent  any  tampering 
with  the  valves.  The  waste  pipe  should  be  carried  far  enough  be- 
yond the  gate-house  to  reach  a  convenient  locality  for  discharging 
readily  the  water  passing  through  it.  The  end  of  the  pipe  should 
be  protected  in  many  cases  by  a  cement  masonry  wall  resting  on  a 
good  foundation,  and  the  ground  immediately  in  front  of  the  end 
of  the  pipe  should  be  paved  with  small  field  stone  to  prevent  the 
washing  away  of  the  earth.  Such  an  arrangement  as  this  is  prob- 
ably as  cheap  as  anything  reliable  that  can  be  designed.  The  ex- 
tra cement  masonry  filling  required  to  form  a  level  surface  at  the 
mouth  of  the  elbow  and  for  the  small  valve  chamber  will  be  less 
expensive  in  most  cases  than  the  standards  and  fittings  necessary 
to  manipulate  the  valves  were  they  placed  in  the  main  well  in- 
stead of  the  small  gate  chamber.  Such  a  system  is  to  be  selected 
foA  the  smallest  works  only,  where  it  is  necessary  to  keep  the  first 
cost  down  to  the  minimum  amount.  The  greatest  depth  of  water 
for  which  the  plan  is  suited  is  not  much  over  10  feet. 

A  somewhat  more  elaborate  gate-house  is  shown  in  Figure  3. 
where  the  valve  chamber  ;s  4  feet  square,  inside  dimensions,  and 
the  walls  are  16  inches  thick.  The  two  pipes,  assumed  to  be  8 
inches  in  diameter,  are  each  provided  with  a  single  gate  valve. 
The  waste  pipe  runs  directly  from  the  outside  face  of  the  wall  and 
has  no  connection  with  the  valve  chamber.  The  main  pipe  ends 
in  a  small  screening  well  about  20  inches  square  and  1  foot  deep. 
This  is  covered  by  a  frame  having  a  screen  of  wire  or  perforated 
plate.  This  frame  can  be  pulled  to  the  surface  whenever  it  is 
necessary  to  clean  it,  and  can  be  placed  in  position  again  without 
much  trouble  with  the  aid  of  a  pole  kept  in  the  valve  chamber* 


WATER-WORKS    MANUAL.  43 

With  this  plan  it  is  proposed  to  draw  water  from  the  reservoir  at 
different  heights  through  sluice  gates  arranged  in  the  manner 
shown  in  Figure  4. 

The  advantage  of  this  method  of  construction  over  the  first  is 
due  to  the  complete  control  of  the  water  at  the  place  where  it 
leaves  the  reservoir  instead  of  below  the  dam.  The  screen  is  hori- 
zontal and  therefore  more  liable  to  become  clogged  than  if  it  were 
placed  in  an  upright  position,  but  on  the  other  hand  the  cost  of 
such  screening  apparatus  is  very  small  as  compared  with  that  of 
the  screens  shown  in  Figure  4.  The  valves  have  bell  ends  and  are 
calked  to  the  pipe  in  the  usual  manner  for  such  valves.  In  the 
cuts  the  vertical  cross-section  is  taken  on  the  line  C  D  and  the 
plan  on  the  line  A  B. 

The  gate-house  shown  in  Figure  4  is  representative  of  the  best 
class  of  such  structures  for  small  works.  It  was  built  recently 
at  Ipswich,  Mass.,  from  plans  prepared  by  Freeman  C.  Coffin,  M. 
Am.  Soc.  C.  E.  The  depth  of  water  in  this  reservoir  above  the 
concrete  foundation  is  about  1 8  feet,  and  two  sluice  gates  are  pro- 
vided by  which  the  supply  can  be  drawn  off  of  the  bottom  of  the 
reservoir  or  from  about  mid-depth.  The  chamber  is  divided  into 
two  portions,  each  8  feet  by  3  feet  2  inches  in  plan,  by  the  double 
set  of  screens  and  the  grooved  masonry  walls  in  which  they  slide 
up  and  down.  These  screens  have  wooden  frames  measuring 
about  4 1  x  4  feet,  four  frames  being  used  for  each  vertical  set. 
The  advantage  of  the  duplicate  screens  is  that  when  one  set  is  re- 
moved for  cleaning,  the  second  set  is  still  in  place  to  prevent  the 
.entrance  of  large  solids  into  the  main  pipe.  The  discharge 
pipe,  it  will  be  noticed,  has  no  communication  with  the  gate 
chamber  in  which  its  valve  is  located.  The  flow  of  water  into  the 
main  pipe  is  controlled  by  a  sluice  gate  with  a  flange  connection, 
by  which  it  is  bolted  to  the  end  of  the  pipe.  The  top  of  the  gate 
chamber  is  provided  with  a  brick  arch  carrying  the  floor,  which 
has  a  trap  door  through  which  the  screens  can  be  raised  or  low- 
ered. The  gangway  to  the  gate-house  from  the  embankment  is 
carried  by  two  6-inch  16-pound  I  beams,  and  has  a  light  railing 
made  of  1-inch  and  1^-inch  gas  pipe.  The  bank  end  of  the  gang- 
way is  supported  by  two  6-inch  vertical  pipes  resting  on  blocks  of 
concrete  imbedded  in  the  dam.  An  8-inch  channel  iron  is  laid 
over  the  top  of  the  two  pipes,  and  the  beams,  channel,  and  pipes 
are  united  by  a  few  rivets  and  pieces  of  angle  iron. 


44  WATER-WORKS    MANUAL. 

WASTE  WEIRS. 

The  safety  of  an  earthen  dam  depends  in  a  great  measure 
on  the  proper  proportioning  and  construction  of  the  waste 
weir  by  which  the  surplus  water  in  the  reservoir  may  be 
discharged.  The  first  step  in  designing  such  a  work  is  to  ascer- 
tain the  probable  maximum  run-off  of  the  watershed  above  the 
dam  and  prepare  the  plans  so  that  this  entire  volume  may  be  dis- 
charged without  allowing  the  high-water  level  in  the  reservoir  to 
rise  above  the  elevation  assumed  in  designing  the  embankment. 
An  examination  of  the  site  of  the  reservoir  will  often  furnish  in- 
dications of  the  great  floods  in  the  stream  to  be  impounded,  and 
valuable  information  can  generally  be  secured  from  the  residents 
in  the  vicinity.  It  is  particularly  important  to  remember  that 
the  discharge  per  square  mile  of  small  watersheds  is  liable  to  be 
excessive  when  compared  with  that  of  larger  areas.  Capt.  James 
L.  Lusk,  of  the  Corps  of  Engineers,  United  States  Army,  recently 
made  a  valuable  compilation  of  the  freshet  discharges  from  water- 
sheds of  moderate  area;  this  is  not  easily  accessible,  so  the  most 
important  figures  are  reproduced  in  Table  No.  4. 

Table  A~o.  4. — Freshet  Discharges  in  Cubic  Feet  per  Second  per  Square 
Mile  from  Small  Watersheds. 

Dis- 

Watershed.                               Year.  Area.  charge. 

South  Branch,  N.  Y 1869              7.8  73.92 

Woodhull  reservoir,  N.  Y 1869              9.4  77.76 

Stony  Brook,  Mass 1886  12.7  121.03 

West  Branch,  Croton  River,  N.  Y 1874  20.4  54.43 

Watuppa  Lake,  Mass 1875  28.5  72.00 

South  Fork  Creek,  Pa 1889  48.6  215.11 

Flat  River,  R.  1 1843  61.0  120.85 

Sudbury  River,  Mass 1886  75.2  44.26 

Rock  Creek,  D.  C 1856  77.1  126.40 

Additional  information  bearing  on  the  subject  can  be  gathered 
from  statistics  of  rainfall  in  the  vicinity,  if  such  have  been  kept; 
it  is  surprising  how  many  amateur  meteorologists  there  are 
throughout  the  country,  and  a  diligent  inquiry  will  generally  se- 
cure some  valuable  information  on  heavy  storms.  Such  figures, 
however,  must  be  regarded  as  guides  rather  than  as  limits,  for  the 
waste  weir  must  be  large  enough  to  discharge  a  greater  quantity 
than  has  ever  been  measured,  or  the  probabilities  are  that  sooner 
or  later  the  dam  will  be  overtopped.  In  reporting  on  this  matter 
to  the  Boston  Water  Board,  the  late  James  B.  Francis,  whose 
knowledge  of  rainfall  and  stream  flow  was  remarkable,  advised 


WATER-WORKS    MANUAL.  45 

proportioning  the  arrangements  for  the  discharge  of  surplus 
water  so  that  their  capacity  would  he  equivalent  to  a  rainfall  of  6 
inches  in  depth  in  24  hours  over  the  whole  watershed.  This  is 
several  times  the  largest  measured  rainfall.  Mr.  Fteley  made  the 
same  recommendation  in  a  report  to  the  Aqueduct  Commissioners 
of  Xew  York  City.  His  report  reads  as  follows: 

"As  to  the  capacity  of  the  overflow,  it  is  necessary  to  depart 
from  precedents  on  account  of  the  extent  of  the  watershed  and 
the  comparatively  heavy  rainfalls  that  occasionally  occur  in  the 
Croton  basin.  Judging  from  the  possibilities  of  rain  or  thaw  in 
this  and  neighboring  watersheds,  the  flowing  capacity-  of  the  over- 
flow should  not  be  less  than  equivalent  to  the  flow  in  24  hours  of 
a  volume  of  water  represented  by  a  uniform  thickness  of  6  inches 
over  the  whole  watershed. 

"It  is  true  that  no  such  flow  is  on  record,  and  the  actual  flow 
may  never,  it  is  hoped,  come  to  that  figure,  but  a  combination  of 
adverse  circumstances,  such  as  an  exceptionally  heavy  rainfall  oc- 
curring at  a  time  when  the  ground  is  covered  with  snow,  can  bring 
about  such  a  condition  of  things,  and  it  is  wise  to  be  prepared  for 
it.  It  can  be  so  much  more  readily  done  that  an  increase  in  the 
length  of  the  overflow  can  be  obtained  at  a  comparatively  small 
cost. 

"The  writer  having  had  occasion  to  design  the  overflow  of  sev- 
eral dams  on  an  equivalent  basis,  may  be  allowed  to  state  that,  on 
the  occurrence  of  a  freshet  which  produced  a  flow  somewhat  less 
than  one-half  of  the  quantity  just  mentioned,  he  could  not  but 
feel  in  accordance  with  the  sentiment  of  the  people  living  lower 
down  in  the  valley,  that  the  channels  of  discharge  were  none  too 
large." 

Many  attempts  have  been  made  to  formulate  a  mathematical 
expression  for  the  discharge  from  a  watershed,  but  no  one  expres- 
sion has  yet  been  obtained  which  will  give  more  than  approximate 
indications.  India  has  been  particularly  prolific  in  producing 
these  formulas,  and  Mr.  H.  M.  Wilson,  M.  Am.  Soc.  C.  E.,  states 
the  following  are  two  of  those  most  used  in  that  country: 


Ryves'  formula,  D  —  c  tf  ^L- 
Dickens'  formula,  D  =  c  \/  A* 

where  A  is  the  area  of  the  catchment  basin  in  square  miles;  c  is  a 
coefficient  depending  for  its  value  upon  rainfall,  slope,  soil,  and 


46  WATER-WORKS    MANUAL. 

other  local  conditions;  and  D  is  the  discharge  in  cubic  feet  per 
second.  In  the  Dickens  formula,  the  value  of  c  for  places  where 
the  maximum  rainfall  in  24  hours  is  3.5  to  4  inches  varies  from 
200  for  flat  country  to  300  for  hill  country.  Where  the  maximum 
rainfalls  is  6  inches  the  coefficient  ranges  from  300  to  350.  For 
the  Ryves  formula,  the  coefficient  varies  between  400  and  500,  and 
for  very  hilly  areas,  where  the  maximum  rainfall  is  high,  it  may 
reach  as  high  as  650.  Col.  J.  T.  Fanning,  M.  Am.  Soc.  C.  E.,  has 
given  the  following  formula  as  an  approximate  expression  of  the 
mean  maximum  discharge  from  a  number  of  American  water- 
sheds: 

D  =  200  y~T* 

Although  such  formulas  have  been  employed  to  a  considerable 
extent  in  the  past,  they  are  really  of  little  value  except  as  checks 
on  estimates  of  flood  discharge  obtained  in  other  more  reliable 
ways,  and  in  designing  waste  weirs,  if  the  estimates  exceed  the  re- 
sults given  by  the  formulas  they  should  certainly  be  used.  Mr. 
Desmond  FitzGerakl  makes  this  very  important  statement  con- 
cerning iSrew  England  watersheds  in  his  able  paper  on  "Rainfall, 
Flow  of  Streams  and  Storage/'  previously  referred  to:  "The  water- 
works engineer  who  is  constantly  designing  waste  weirs,  dams, 
reservoirs,  etc.,  may  find  it  convenient  to  bear  in  mind  that  I 
square  mile  of  land  surface  yields  approximately  1.5  cubic  feet  per 
second  throughout  the  year,  and  that  the  maximum  freshet  flow 
may  be  a  hundred  times  this  amount,  or  150  cubic  feet." 

The  location  of  the  spillway  through  which  the  waste  water 
flows  from  the  reservoir  must  of  course  be  determined  by  local 
conditions,  but  prudence  demands  that  wherever  possible  it  should 
be  around  rather  than  over  the  dam,  eyen  where  the  cost  of  this 
plan  is  somewhat  greater.  No  matter  where  it  is  located,  its  di- 
mensions should  be  selected  only  after  careful  consideration.  It 
is  now  the  opinion  of  a  large  number  of  engineers  that  water- 
works reservoirs  should  not  be  provided  with  the  movable  flash- 
|  boards  on  the  waste  weirs,  which-  were  quite  common  in  small 
works  until  recently.  These  engineers  claim  that  it  is  safer  in  the 
end  and  possibly  as  economical,  in  view  of  the  employee's  time  re- 
quired to  watch  the  flashboards,  to  make  the  sill  of  the  waste  weir 
the  maximum  level  of  impounded  water  in  the  reservoir  and  never 
attempt  to  raise  the  water  higher.  This  provision  calls  for  long 
rather  than  deep  waste  weirs. 


WATER-WORKS    MANUAL.  47 

An  old  and  frequently  quoted  rule  for  ascertaining  the  approxi- 
mate length  of  a  waste  weir  is  to  make  it  3  feet  long  for  each  100 
acres  in  the  catchment  area.  Just  who  originated  this  rule  the 
writer  has  never  been  able  to  ascertain,  but  it  leans  toward  safety, 
and  for  areas  exceeding  3  square  miles  gives  an  excessive  length. 
For  smaller  areas  it  seems  to  furnish  a  useful  approximate  method 
of  calculation,  while  for  larger  areas  Mr.  E.  Sherman  Gould's  for- 
mula is  more  in  accordance  with  practice.  The  latter  expression 

is: 

L  =  20  yA 

where  L  is  the  length  of  the  weir  in  feet  and  A  is  the  area  of  the 
catchment  basin  in  square  miles.  To  find  the  depth  of  water  in 
feet,  H,  on  the  weir  when  the  maximum  flood  discharge  Q  is  pass- 
ing over  it,  it  is  necessary  to  employ  the  following  formula: 

H  =  0.459^g'  -H  L». 

This  height  added  to  the  elevation  of  the  sill  of  the  weir  gives 
the  maximum  water  level  in  the  reservoir,  and  the  dam  must  rise 
at  least  3  or  4  feet  above  this  in  order  to  prevent  it  being  overtop- 
ped by  waves.  Mr.  Gould  has  suggested  that  the  depth  of  water 
on  the  sill,  when  a  flood  volume  of  150  cubic  feet  per  second  per 
mile  is  passing  over  a  weir  of  length  of  ZQy'A  may  be  ex- 
pressed with  sufficient  accuracy  for  most  purposes  by  the  simple 
expression: 

H=  1.77  y A. 

It  must  be  distinctly  understod  that  these  formulas  and  rules 
are  only  fair  approximations,  and  that  after  the  weir  is  designed 
and  the  shape  of  the  sill  and  ends  determined,  a  more  exact  com- 
putation, using  the  proper  weir  formula  for  the  conditions,  will 
probably  indicate  a  variation  of  perhaps  as  much  as  10  per  cent, 
from  the  first  calculations.  It  may  even  be  necessary  to  alter  the 
length  of  the  weir  slightly  to  give  it  the  requisite  capacity.  The 
latest  editions  of  Trautwine's  Pocket-Book,  as  well  as  all  books  on 
hydraulics,  give  such  full  information  on  weir  formulas  that  it  is 
unnecessary  to  go  into  the  subject  in  this  place. 

The  waste  weir  of  an  earthen  dam  is  really  a  different  kind  of  a 
dam  connecting  the  two  portions  of  the  embankment,  and  it  is 
therefore  very  important  that  the  surfaces  of  contact  where  the 
different  materials  join  should  be  so  arranged  as  to  prevent  the 
leakage  of  water.  In  this  case,  again,  the  maxim,  "water  abhors 


48 


WATER-WORKS    MANUAL. 


an  angle,"  is  the  golden  rule  of  success.  The  earth  bank  on  each 
side  of  the  weir  must  be  held  by  wing  walls  of  some  form,  and 
these  walls  must  be  carried  down  to  good  foundations.  There  is 
one  not  uncommon  exception  to  this  rule,  which  is  made  when  the 
dam  has  to  be  founded  on  sandy  soil,  such  as  underlies  all  the 
reservoirs  of  the  Brooklyn  water-works.  The  method  of  treat- 
ment in  such  cases  was  introduced  many  years  ago  by  the  late 
James  P.  Kirkwood,  and  has  been  followed  with  success  in  many 
subsequent  structures,  one  of  the  latest  being  the  new  dam  of  the 
Syracuse  water-works  at  Skaneateles  Lake.  It  may  be  best  de- 
scribed by  abridging  Mr.  Kirkwood's  account  of  the  construction 


Water  Level 


Scale 
10' 


20' 


Water  Level. 


FIGURE  5.— WASTE- WEIR  ON  SAND  FOUNDATION. 

of  the  weir  of  the  Jamaica  reservoir  dam,  an  earthen  embankment 
with  a  puddle  center  wall. 

The  bottom  of  the  reservoir  is  fine  sand  and  gravel  of  the  same 
character  as  the  material  of  the  surrounding  plain,  and  the 
earthen  dam  has  a  puddle  wall  in  the  center  made  of  fine  gravel 
and  sand.  The  general  form  of  the  waste  weir,  which  has  a  clear 
length  of  21  feet,  is  shown  in  Figure  5. 

The  masonry  is  granite  laid  in  hydraulic  cement  mortar,  and 
rests  on  a  timber  platform  arranged  as  shown  in  the  illustration. 
In  order  to  prevent  an  excessive  leakage  of  water  under  the  plat- 


WATER-WORKS    MANUAL.  49 

form,  a  row  of  sheet  pilling  was  driven  on  its  upper  side  and  ex- 
tended a  short  distance  into  the  bank  at  either  end  of  the  ma- 
sonry. The  specifications  required  this  piling  to  be  driven  to  a 
depth  of  at  least  12  feet,  but  this  clause  was  not  carried  out.  The 
result  was  that  the  platform  was  undermined  by  water  and  had  to 
be  rebuilt  with  sheet  piling  in  conformity  with  the  requirements 
of  the  engineer.  Two  openings  were  left  in  the  masonry,  as 
shown  in  the  illustration,  to  allow  free  passage  of  the  water  of  the 
brook  during  the  construction  of  the  works.  These  openings 
were  afterward  closed  and  the  upper  face  of  the  overfall,  toward 
the  reservoir,  covered  with  earth.  It  will  be  noticed  that  the 
masonry  of  one  wall  has  two  buttresses.  These  were  provided  to 
break  the  surface  and  prevent  leakage  along  the  back  of  the  wall, 
and  as  a  further  precaution  the  puddle  wall  was  increased  in 
width  as  it  approached  the  masonry,  until  it  covered  the  entire 
space  between  the  buttresses.  The  masonry  of  the  other  wing 
wall  was  continued  to  form  a  sluiceway,  which  is  not  shown  in  the 
cut.  The  pavement  on  the  apron  was  laid  in  courses  with  cement 
mortar,  and  was  continued  down-stream  by  a  mass  of  rubble  to 
protect  the  sheet  piling  at  that  place  from  eddies. 

Such  a  method  of  construction  would,  of  course,  be  dangerous 
where  it  was  not  certain  that  the  timber  platform  would  remain 
below  the  permanent  level  of  the  ground  water. 

The  cross-section  of  the  masonry  of  the  weir  is  typical  of  the 
form  generally  given  to  such  structures  which  are  not  much  more 
than  10  feet  high.  The  section  is  calculated  by  the  same  methods 
as  a  masonry  dam.  The  down-stream  face  is  usually  given  a 
slight  batter,  2  inches  to  the  foot.  The  design  of  the  top  is  really 
the  part  calling  for  the  most  judgment,  since  its  width  must  be 
decided  upon  after  studying  the  probable  character  of  the  debris 
that  will  pass  over  it.  If  it  is  certain  that  no  logs  or  other  heavy 
masses  will  ever  be  driven  against  it,  then  its  slope  may  be  slight, 
say  2  inches  to  the  foot,  and  its  width  kept  down.  But  if  logs, 
and  broken  ice  are  to  pound  against  it  during  every  spring  freshet,, 
then  the  slope  may  be  made  a  little  greater,  so  that  the  logs  and 
ice  will  be  more  likely  to  strike  on  it  during  floods  than  on  the 
face  of  the  dam  itself.  The  width  in  this  case  must  be  ample  to 
insure  perfect  security,  and  the  stones  of  the  sill  should  be  large 
and  heavy,  cut  to  shape  accurately  and  well  bound  together.  Just 
what  width  to  select  for  a  given  case  cannot  be  expressed  in  a  rule, 


50  WATER-WORKS    MANUAL. 

but' must  be  determined  by  judgment  aided  by  established  prece- 
dent. The  slope  of  the  upstream  face  is  made  so  as  to  give  a  dam 
of  the  requisite  degree  of  security.  If  the  weir  is  more  than  about 
10  feet  high  its  down-stream  face  should  be  stepped  so  as  to  break 
the  fall  of  the  water  and  diminish  its  erosive  action  on  the  bottom, 
as  will  be  explained  more  fully  in  the  chapter  on  masonry  dams. 
In  any  case  particular  attention  should  be  paid  to  protecting  the 
surface  on  which  the  water  strikes.  This  is  frequently  done  by  a 
pavement  of  stones  about  the  size  of  granite  paving  blocks,  laid  in 


1-44.00 


Scale. 
0'  I'  2'  3'  4'  5'  G'  7 


~\ 


+44.  25 


Profile     ot    Bridge. 


Cross -Sect  ion    below  Planks. 

6.— WASTE  WEIR  AT  NATICK,  MASS. 


cement  mortar  and  resting  on  a  well-consolidated  bed  of  gravel  or 
field  stone,  but  many,  other  methods  of  construction  have  been 
used.  , 

A  waste  weir  used  on  a  spillway  at  one  side  of  a  small  earth  dam 
at  Natick,  Mass.,  is  shown  in  Figure  6.  It  was  designed  by  Mr. 
Desmond  FitzGerald,  and  may  be  taken  as  a  model  for  small  work 
where  the  spillway  is  around  and  not  over  the  dam. 

Timber  weirs  do  not  possess  the  durability  of  well-built  ma- 
sonry structures,  yet  they  have  many  good  features.  When  con- 


WATER-WORKS    MANUAL.  51 

structed  properly  they  last  many  years,  and  such  repairs  as  a  good 
timber  weir  requires  can  generally  be  made  expeditiously  and  at 
a  very  small  expense.  The  form  given  such  weirs  varies  greatly, 
just  as  the  form  and  method  of  construction  of  timber  dams  seem 
to  follow  no  fixed  types.  Col.  J.  T.  Fanning  illustrates  quite  an 
elaborate  weir  of  this  sort  (see  Figure  7)  in  his  "Treatise  on  Hy- 
draulic Engineering/'  The  timbers  in  it  are  stripped  of  bark  and 
dressed  on  two  sides  to  a  thickness  of  12  inches.  The  purpose  of 
the  sheet  piling  is  to  check  the  percolation  of  water  under  the 
dam.  The  timbers  laid  on  the  sills  are  5  feet  apart,  and  on  these 
the  frame  is  built  up  as  shown.  The  sticks  are  united  by  J-inch 


FIGURE  7.— A  TIMBER  WEIR. 

round  iron  drift  bolts  long  enough  to  pass  through  two  timbers 
and  a  half  way  into  the  third.  As  the  frame  is  built  up,  the  open- 
ings must  be  packed  tight  with  stone  and  gravel  of  such  propor- 
tions that  the  work  will  be  watertight,  a  matter  requiring  care  and 
thoroughness  to  be  successful.  The  benches  and  crest  should  be 
made  of  carefully  jointed  timbers  laid  close,  and  the  upper  and 
lower  faces  covered  with  tightly  jointed  plank.  If  such  a  weir  has 
to  be  founded  on  rock,  the  bottom  courses  of  timber  should  be 
bolted  firmly  to  the  rock. 

Whether  the  weir  be  masonry  or  timber,  a  bank  of  gravel  should 
be  placed  against  its  up-stream  face. 


CHAPTER  IV.— TIMBER  DAMS. 

The  timber  dam  is  often  regarded  as  a  cheap  makeshift,  good 
enough  for  temporary  use,  but  never  to  be  mentioned  to  clients  as 
a  structure  of  any  engineering  importance  and  never  to  be  recom- 
mended except  for  situations  where  other  engineers  will  probably 
never  see  it  and  thus  have  a  chance  to  laugh  at  its  designer.  Re- 
cently, however,  engineers  of  high  standing  have  designed  such 
dams  for  situations  where  permanence  and  durability  were  neces- 
sary, and  the  feeling  is  growing  that  timber  dams  of  some  of  the 
types  which  have  stood  for  many  years  on  New  England  mill  sites 
and  along  the  canals  of  the  Eastern  States  are  deserving  of  more 
attention.  Whether  or  not  such  a  structure  should  be  built  de- 
pends largely  on  its  cost  compared  with  earth  and  masonry  dams, 
and  on  the  nature  of  the  work  that  will  be  necessary  to  replace  it 
when  complete  reconstruction  becomes  necessary.  It  will  some- 
times be  found  that  a  small  dam  will  impound  a  sufficiently  large 
supply  to  enable  a  community  to  have  all  the  water  it  wants  for  a 
period  of  15  to  20  years,  when  the  normal  growth  will  require  a 
daily  supply  that  can  only  be  obtained  by  the  construction  of  a 
reservoir  in  another  locality.  In  case  the  construction  of  this 
large  reservoir  should  be  more  costly  per  million  gallons  stored 
than  that  of  the  smaller  reservoir,  then  it  may  be  good  practice 
to  build  the  latter,  and  in  such  a  case  a  timber  dam  may  afford  a 
safe  and  cheap  means  of  accomplishing  this  end.  In  a  very  gen- 
eral way  it  may  be  estimated  that  a  large  well-built  timber  dam 
will  cost  about  one-half  or  three-fifths  as  much  as  a  masonry  dam 
of  the  same  height  and  will  last  half  a  century  with  but  very  little 
outlay  for  repairs,  while  the  cost  may  be  reduced  very  much  with- 
out impairing  the  safety  of  the  structure  by  using  less  care  in  the 
construction.  Small  timber  dams  may  often  be  constructed  at  a 
remarkably  small  cost:  It  must  not  be  forgotten,  however,  that 
timber  must  be  continually  below  the  surface  of  the  water  if  it  is 
to  remain  in  sound  condition,  and  on  this  account  timber  dams 


WATER-WORKS    MANUAL.  53 

are  more  suitable  for  diversion  weirs  for  directing  part  of  the  water 
of  a  river  into  a  canal  than  they  are  for  storage  reservoirs. 

BRUSH  DAMS. 

The  brush  and  rock  dam  of  the  Western  States  is  merely  a 
makeshift,  but  in  case  it  is  necessary  to  build  a  dam  not  over  6 
feet  high  across  a  stream  having  a  quicksand  foundation  this  type 
of  a  structure  may  serve  a  very  useful  temporary  purpose.  Mr. 
W.  W.  Follett,  M.  Am.  Soc.  C.  E.,  who  has  an  extensive  acquaint- 
ance with  irrigation  works,  recommends  tying  the  brush,  prefer- 
ably willow,  into  fascines  6  to  8  inches  in  diameter.  The  back  of 
the  dam  may  be  quite  steep,  but  the  front  should  slope  very  gradu- 
ally in  order  that  the  water  may  leave  the  brush  almost  horizon- 
tally. A  more  elaborate  affair  is  sometimes  constructed  by  driv- 
ing piles  and  building  brush  and  rockwdrk  around  them,  the 
whole  being  provided  with  a  timber  overfall,  or  upper  covering, 
and  apron. 

In  the  streams  where  such  structures  are  employed,  the  brush 
and  rock  are  usually  to  be  obtained  near  at  hand,  and  when  placed 
in  position  are  soon  silted  into  a  fairly  tight  dam  by  the  fine  sand 
and  sediment  in  suspension  in  the  water.  If  a  rapid  rise  carries 
the  whole  work  downstream  the  loss  is  slight  and  can  be  quickly 
<and  cheaply  made  good  again.  These  dams  were  used  by  the  early 
Spanish  settlers  in  the  Southwest,  and  such  a  weir  of  very  small 
size  has  been  employed  until  recently,  and  may  be  still,  at  the 
head  of  the  Zanja  Madre,  the  main  irrigating  ditch  of  Los  An- 
geles. 

Somewhat  pretentious  dams  of  this  sort  were  constructed  near 
Phoenix,  Ariz.  According  to  Mr.  Herbert  M.  Wilson,  M.  Am. 
Soc.  C.  E.,  they  were  built  by  driving  stakes  into  the  river  bed 
across  the  channel.  Between  these,  fascines  of  willows,  about  3 
inches  in  diameter  at  the  butts,  were  laid  with  the  butts  down- 
stream, their  upper  branches  being  loaded  with  boulders.  Wil- 
lows, cottonwood  and  tule  reeds  were  again  laid  and  covered  with 
boulders,  and  this  repeated  until  the  dam  reached  the  desired 
height,  which  rarely  exceeded  5  feet.  If  not  destroyed  too  soon 
the  willows  sprout  and  thus  increase  the  strength  of  the  structure, 
which  is  rendered  water-tight  by  an  up-stream  filling  of  sand  and 
gravel. 

A  dam  of  almost  as  primitive  construction  is  used  on  Cherry 


54  WATER-WORKS    MANUAL. 

Creek,  Colo.,,  at  the  head  of  the  Arapahoe  Canal.  It  is  96  feet 
long  and  10  feet  in  maximum  height.  Piles  about  26  feet  long 
and  6  feet  center  to  center,  driven  in  two  lines  across  the  stream, 
were  covered  on  each  face  with  2-inch  planks,  so  as  to  form  a  long 
box.  About  60  feet  of  this  box  was  left  3  feet  lower  than  the  rest 
to  form  an  overflow  weir,  and  the  whole  was  then  filled  with  sand. 
Adjoining  this  structure  is  a  rubble  masonry  dam  containing  the 
headgates  of  the  canal. 

CRIB  DAMS. 

It  is  customary  to  draw  a  distinction  between  crib  and  framed 
dams,  but  the  two  classes  frequently  run  together.  The  typical 
crib  dam  is,  as  its  name  implies,  made  of  a  number  of  separate 
cribs,  usually  placed  in  position  independently  and  then  connect- 
ed by  other  cribs  inserted  between  them  or  by  bulkheads  backed 
by  loose  stone.  The  term  has  been  extended  to  embrace  contin- 
uous dams  framed  to  form  cribs,  but  this  use  of  the  expression  is 
somewhat  confusing. 

A  true  crib  dam  was  described  by  Mr.  T.  C.  Clarke,  M.  Am.  Soc. 
C.  E.,  in  the  "Transactions"  of  the  American  Society  of  Civil  En- 
gineers, Volume  xxxiv.,  page  507.  It  was  so  designed  as  to  be 
available  for  use  on  any  kind  of  a  foundation.  If  the  river  bed  is 
sand,  riprap  is  thrown'on  it  above  and  below  as  well  as  at  the  site 
of  the  cribs,  so  as  to  protect  the  bottom  from  scouring.  The  cribs 
are  20  to  30  feet  long,  filled  with  stone,  and  placed  in  such  a  way 
that  openings  5  to  8  feet  long  are  left  for  the  discharge  of 
the  stream  during  construction.  The  cribs  are  filled  with  stone, 
arid  form  piers  on  which  a  continuous  dam  of  triangular  cross- 
section  is  built  from  shore  to  shore.  It  is  built  of  12xl2-inch 
framed  timbers  protected  with-  iron  plates  at  the  crest,  and  is  filled 
with  loose  stone.  The  upstream  face  has  a  slope  of  3  to  1,  and 
the  down-stream  face  a  slope  of  2  to  1.  After  this  work  is  fin- 
ished, the  openings  are  closed  by  gates  of  two  thicknesses  of  12x 
12-inch  timber  drift-bolted  together. 

The  crib  dams  built  at  the  head  of  the  Arizona  are  good  ex- 
amples of  this  type  of  structure,  and  incidentally  furnish  also  a 
strong  proof  of  the  advisability  of  locating  and  building  dams  in 
torrential  streams  in  the  best  manner.  Both  the  dams  to  be  il- 
lustrated were  destroyed  by  floods,  not  so  much  on  account  of 
their  faulty  construction  as  on  account  of  their  unsuitability  for 
the  place  and  their  bad  location,  features  which  the  company's 


WATER-WORKS    MANUAL. 


55 


engineer  had  forced  upon  him.     In  a  stream  not  subject  to  such 
freshets  they  would  probably  have  been  satisfactory. 

The  design  of  the  first  weir  is  shown  in  Figure  8,  and  its  method 
of  construction  is  described  in  substance  as  follows  in  the  thir- 
teenth Annual  Report  of  the  U.  S.  Geological  Survey:  The  bed 
of  the  stream  was  first  prepared  for  receiving  the  dam  by  dump- 
ing stone  on  the  bottom  from  a  pontoon  moored  up-stream.  The 
stone  was  in  pieces  weighing  from  1  to  3  tons,  and  was  used  in 
such  a  quantity  that  it  formed  a  bar  across  the  channel  over  which 
the  water  passed.  The  stream  carries  considerable  sediment  and 


Rough  Stone 


Facmes 

Small  Rubble, 


Facines. 


•Large  Rubble 


Large 
Rubble 


UIPI™ 


FIGURE  8.— CRIB  AND  RUBBLE  DAM. 


shingle,  and  the  interstices  in  this  rubble  were  soon  filled  up. 
Th?  cribs  were  22  feet  long  and  12  feet  wide,  and  of  a  height  cor- 
responding to  that  of  the  weir  at  the  place  where  they  were  to  be 
used.  They  were  built  on  shore  and  floated  into  position;  when 
located  in  the  diagonal  manner  indicated  in  the  cut  they  were 
sunk  by  dumping  stone  on  the  2-inch  plank  bottom  spiked  to  the 
lower  logs.  At  the  up-stream  toe  of  the  wall  formed  in  this  man- 
ner a  bed  of  willow  fascines  2  feet  thick  was  laid  parallel  with  the 
direction  of  the  current  and  beyond  them  five  rows  of  similar 
fascines  at  right  angles  to  the  first.  Boulders  and  gravel  were 
then  thrown  on  this  work  until  the  whole  mass  was  brought  to 
the  level  of  the  top  of  the  cribs,  where  it  was  bound  together  with 


56  WATER-WORKS    MANUAL. 

fascines.    The  remaining  features  of  the  dam  are  indicated  in  the 
illustration. 

The  second  of  these  weirs  is  shown  in  Figure  9,  also  drawn  from 
"ithe  same  source.    Here  the  crib  idea  was  developed  in  the  simplest 


'Plank, 


nF^^^ 

—  q 

'PL.  c 

b  r 

(J           C 

^1  LJ 

+— 

^ 

T  C 

b  r 
u            c 

b  —  i 

?\:£^\/-\'- 

FIGURE  9. -CRIB  DAM  ON  ARIZONA  EIVER. 

manner,  the  cross-section  of  the  dam  being  formed  by  five  9-foot 
cribs  of  rough  logs,  drift-bolted  and  wired  together,  and  loaded 
with  rocks.  These  cribs  were  not  constructed  in  precisely  the 
same  manner  throughout  the  entire  length  of  the  dam,  but  the 
general  cross-section  was  the  same  everywhere. 

FRAMED   DAMS. 

One  of  the  most  remarkable  framed  dams  with  which  the 
author  is  acquainted  is  that  built  by  Mr.  Eobert  Oilman  Brown  at 
Bodie,  Cal.,  for  the  Standard  Consolidated  Mining  Company. 
From  a  description  of  the  structure  which  he  prepared  for  the 
Colorado  meeting  of  the  American  Institute  of  Mining  Engineers, 
it  appears  that  its  leading  dimensions  are  as  follows: 

Length  at  bottom,  80  feet;  length  on  top,  235  feet;  width  at 
bottom,  60  feet;  width  on  top,  15  feet;  height,  42  feet;  batter  of 
water  face.  1  to  1  and  1  to  2;  batter  of  free  face,  1  to  4;  length  of 
waste  weir,  35  feet;  depth  of  spillway,  5  feet. 

An  inspection  of  the  details  of  construction  shown  in  Figure  10 
will  indicate  the  peculiarities  of  this  dam.  In  a  general  way  it 
may  be  described  as  a  structure  of  logs  framed  into  12-foot  cribs, 
ballasted  with  earth  and  rock,  and  sheathed  on  its  up-stream  face 
with  3-inch  plank.  Only  enough  hewing  was  done  to  bring  the 
logs  into  close  contact,  and  the  sticks  were  secured  by  drift  bolts 
except  for  a  few  of  the  upper  tiers,  where  wooden  pins  were  used. 
The  bottom  and  sides  are  provided  with  sheet  piling  10  feet  long, 
sunk  into  firm  hardpan.  Work  was  begun  at  the  bottom,  and 
after  a  few  courses  of  logs  were  in  place,  the  cribs  were  filled  with 


WATER-WORKS    MANUAL. 


57 


material  excavated  to  form  the  higher  benches.  As  the  height  in- 
creased and  more  material  for  ballast  was  needed,  tramways  were 
laid  up  and  down  stream  on  one  bank  at  the  proper  elevation,  and 
ballast  was  excavated  from  the  bank  and  brought  by  cars  to  the 
dam,  the  tracks  being  shifted  higher  as  the  tiers  of  timber  work 
were  raised.  The  inclined  rafters  for  the  sheathing  were  carried 


Plan    of   Lower     Framin 


9- 


Line  of  Filling.  \        Sheet  Piling. 


Half    Elevation  of  Free  Face.        Half    Elevation  of  Water  Face 


Weir. 


nififi 


Strainer 


Plan    of 
Cross -Section  of   Dam.  LI        Spillway; 

FIGURE  10.— FRAMED  DAM  AT  BODIE,  CAL. 

up  as  rapidly  as  possible,  and  covered  with  horizontal  planks 
calked  carefully  with  tamarack  bark.  This  sheathing  was  backed 
by  clayey  earth  free  from  stones,  which  was  tamped  into  place. 

The  waste  weir  is  lined  with  planks  and  its  sill  is  28  feet  above 
the  top  of  the  strainer.  The  spillway  contracts  from  the  full 
width  of  the  weir  at  the  top  to  18  feet  at  the  bottom,  "with  a 


58  WATER-WORKS    MANUAL. 

slight  inward  batter  of  the  wings,  so  as  better  to  hold  the  splash." 
The  apron  is  made  of  selected  straight  logs  with  hewn  joints, 
drift-bolted  to  four  transverse  mudsills. 

The  outlet  and  waste  pipes  are  both  apparently  of  the  riveted 
type.  The  former  commences  in  a  wooden  strainer  with  half-inch 
wire  screens.  Both  pipes  have  valve  chambers  of  plank  reached 
by  doors  under  the  spillway.  A  fish  ladder  was  provided  in  ac- 
cordance with  State  laws.  Mr.  Brown  reports  that  scarcely  a  trace 
of  leakage  has  been  detected  below  the  dam,  and  that  the  valve 
chambers,  30  feet  below  the  surface  of  the  water,  are  dry. 

About  49,000  feet,  B.  M.,  of  sawn  lumber  were  used  in  the  dam 
proper,  908  logs  and  472  pieces  of  sheet  piling.  The  weir  and 
spillway  required  4,000  feet  of  sawn  lumber  and  the  fish  ladder 
12,000  feet.  About  two-thirds  of  the  cost  of  the  structure  was 
the  labor  charge.  The  average  number  of  men  employed  was  11 
and  the  time  required  to  construct  the  dam  was  26  weeks. 

Structures  of  this  type  are  rarely  built,  since  rock-fill,  earth  and 
masonry  dams  are  generally  more  economical  in  the  long  run, 
when  charges  for  repairs  and  reconstruction  are  taken  into  con- 
sideration. Nevertheless,  experience  in  California  shows  that 
they  are  more  substantial  than  is  generally  believed  to  be  the  case. 

A  much  more  elaborate  framed  dam,  13  2-3  feet  high,  designed 
to  act  as  a  weir  for  its  whole  length,  is  illustrated  in  "The  En- 
gineering Record"  of  April  21,  1894.  This  dam  was  built  at 
Sewall's  Falls,  near  Concord,  N.  II.,  and  is  probably  typical  of  the 
best  practice  for  such  undertakings.  Another  structure  of  this 
class  which  ranks  very  high  is  that  across  the  Missouri  River  at 
Great  Falls,  Mont.,  a  description  of  which,  by  Mr.  M.  S.  Parker,  is 
printed  in  Volume  xxvii.  of  the  "Transactions"  of  the  American 
Society  of  Civil  Engineers. 

Many  of  the  timber  dams  constructed  on  irrigation  works  in  the 
western  part  of  this  country  are  of  much  interest,  and  two  of  them 
are  described  here,  the  descriptions  being  based  on  an  article  on 
"American  Irrigation  Engineering"  in  the  Thirteenth  Annual 
Report  of  the  United  States  Geological  Survey.  Both  are  weir 
dams,  that  is  to  say,  they  are  built  so  that  they  may  be  submerged 
for  their  whole  length  during  floods  without  injury. 

The  first  structure  is  that  across  Stony  Creek,  at  the  head  cf 
the  Kraft  Irrigation  District  in  California.  It  is  500  feet  long 
and  rests  on  the  gravel  bottom  of  the  stream  as  shown  in  Figure 


WA  TER-WORKS    MANUAL. 


59 


11.  The  wing  walls  at  either  end  were  formed  by  piles  and 
sheathing,  raised  to  a  height  believed  to  be  sufficient  to  prevent 
the  greatest  flood  from  passing  over  or  around  them.  The  timber 
frames  rest  on  piles  and  are  filled  with  gravel;  both  faces  are 
framed  with  6x8-inch  timbers.  The  up-stream  face  is  sheathed 
with  3-inch  planking  and  the  lower  face  with  7-inch.  "The  foun- 
dation consists  of  two  rows  of  piles  driven  across  the  entire  width 
of  the  channel  of  the  stream,  6  feet  apart  between  centers,  the 
two  rows  being  12  feet  apart,  one  resting  immediately  under  the 
foot  of  the  timbers  on  the  down-stream  face  of  the  weir,  the  other 
resting  under  the  toe  of  an  apron  which  extends  12  feet  below 
the  weir.  Eight  feet  below  the  lower  row  of  piles  is  a  row  of  sheet 
piling,  and  22  feet  above  the  upper  row  or  just  above  the  upper 


FIGURE  11. -TIMBER  WEIR  ON  STONY  CREEK. 


slope  of  the  weir  is  another  row  of  sheet  piling,  both  of  these  rows 
being  of  4-inch  double  piling  8  feet  in  length  and  driven  to  bed 
rock." 

The  weir  shown  in  Figure  12  differs  from  those  previously  de- 
scribed in  being  bolted  to  a  rock  bottom.  It  is  built  across  the 
Bear  River,  near  Collinston,  Utah,  and  forms  part  of  the  head- 
works  of  the  irrigating  system  in  the  northern  part  of  the  Salt 
Lake  valley.  The  river  at  this  place  has  rocky  banks  and  is  about 
400  feet  wide.  The  timber  dam  shown  in  the  cut  is  370  feet  long 
and  17-J  feet  in  maximum  height.  Its  greatest  width  at  the  base 
is  38  feet.  The  greatest  flood  discharge  of  the  river  at  this  place 
is  estimated  at  about  9,000  cubic  feet  per  second,  and  when  such 
a  volume  of  water  is  passing  the  depth  on  the  crest  of  the  weir  is 


60 


WATER-WORKS    MANUAL. 


considerable.  The  up-stream  face  has  a  slope  of  1  to  2,  and  the 
other  face  a  slope  of  2  to  1.  The  water  falls  on  a  wooden  apron 
built  on  the  prolongation  of  the  sills  of  the  dam.  All  the  timbers 
used  in  the  structure  measure  10x12  inches.  The  spaces  between 
them  are  filled  with  broken  rock,  and  the  up-stream  face  of  the 
weir  is  protected  by  a  mass  of  earth  and  silt  deposited  from  the 
river  water. 

On  one  end  of  this  weir  is  a  masonry  structure  containing  the 
gates  of  the  canal  on  that  side,  while  at  the  other  end  the  head 


'n^/a--W/X:i'-:^/A:.::-V/S;^y/*^W/&::^ 

^^mm^i^^^m^ 


FIGURE  12. -TIMBER  WEIR  ON  BEAR  RIVER. 

works  of  the  corresponding  canal  are  in  a  channel  excavated  in 
the  rock  bank. 

In  the  construction  of  timber  dams  there  is  generally  little  op- 
portunity for  a  choice  in  the  wood  employed.  Nevertheless,  it 
must  be  borne  in  mind  that  certain  woods,  like  hemlock  and 
green  cottonwood,  are  particularly  adapted  for  use  under  water, 
and  a  careful  investigation  of  the  varieties  of  available  timber  may 
have  good  results  when  an  engineer  has  to  erect  one  of  these  struc- 
tures in  a  locality  with  which  he  is  unfamiliar. 


CHAPTER  V.— MASONRY  DAMS. 

Before  taking  up  the  method  of  designing  small  masonry  dams, 
it  is  necessary  to  call  attention  to  a  few  general  features  of  reser- 
voir construction.,  which  must  he  studied  with  particular  care 
when  a  masonry  dam  is  to  he  used.  The  first  of  these  is  the  nature 
of  the  site.  On  this  point,  the  following  very  general  remarks  by 
Otto  Lueger  (translated  from  his  "Water  Supply  of  Cities")  give 
a  fair  idea  of  the  influence  of  the  site  of  a  proposed  reservoir  on 
the  design  of  the  dam  forming  it: 

"It  is  assumed  that,  as  a  rule,  a  clay  stratum  of  at  least  5  feet 
is  sufficient  to  form  a  reservoir  with  an  impervious  bottom,  espec- 
ially in  view  of  the  deposits  of  silt  which  will  inevitably  be  formed 
later  and  increase  the  tightness.  In  the  first  place,  then,  it  is 
necessary  to  ascertain  if  such  a  deposit  exists.  Next,  the  strata 
below  this  bed  are  to  be  investigated.  If  the  clay  reaches  to  a 
great  depth  before  encountering  rock,  an  earth  embankment  is 
most  suitable  for  a  dam.  If  it  is  possible  to  satisfy  the  require- 
ments with  a  dam  75  feet  or  less  in  height,  such  a  structure  will 
be  safe  if  carefully  built  and  the  strata  are  horizontal  or  nearly 
so.  If  they  are  much  inclined  and  are  underlaid  by  material 
which  will  flow  when  continually  moist  or  become  so  unstable  that 
the  earth  above  will  slide  under  similar  conditions,  the  construc- 
tion of  the  dam  is  to  be  positively  condemned;  also  in  the  case  of 
nearly  horizontal  strata,  the  material  below  the  dam  must  be  com- 
pressed if  every  danger  to  the  earth  bank  is  to  be  avoided.  Em- 
bankments more  than  75  feet  high  are  dangerous  under  all  cir- 
cumstances, because  their  saturation  becomes  too  great  under  the 
high-water  pressure.  On  rocky  ground,  embankments  should  not 
be  built,  but  only  masonry  darns  constructed. 

"Among  rocks  those  of  eruptive  stone,  granite,  porphyryte, 
basalt,  trachyte,  etc.,  offer  the  safest  foundation  for  the  dams. 
The  stratified  rocks  do  not  always  afford  a  safe  .bed,  less  on  account 
of  their  strength  than  on  account  of  their  position  and  cleavage. 


62  WATER-WORKS    MANUAL. 

Nevertheless  it  is  generally  safe  to  build  on  them  if  they  are  split 
but  little,  and  nearly  or  quite  horizontal,  or  if  the  layers  are  in- 
clined downward  toward  the  reservoir  from  the  site  of  the  dam. 
Care  must  be  taken  in  this  case  also  to  avoid  the  presence  of  marl 
or  clay  strata  under  the  foundation  of  the  dam;  these  might  be- 
come saturated  by  the  water  in  the  basin  and  made  plastic  or 
brought  to  a  condition  in  which  they  would  flow.  It  is  therefore 


Beaver      Creek       Reservoir 
Plan. 


Rock 


El  evot  t  i  o  n. 

FIGURE  13.  -  MASONRY  DAM  AT  LITTLE  FALLS. 

advisable  to  ascertain  the  character  of  such  stratified  formations 
by  careful  examinations,  test  borings,  etc.,  before  the  position  of 
the  dam  is  definitely  decided.  This  is  still  more  important  when 
it  appears  probable  that  cracks  and  deep  fissures  exist.  If  the  site 
of  the  proposed  dam  is  on  the  outcrop  of  the  strata,  it  is  possible 
under  certain  conditions  that  the  base  will  be  exposed  to  great 
danger  of  undermining,  especially  if  a  clay  or  marl  substratum  ex- 


WATER-WORKS    MANUAL.  itt 

ists,  as  is  frequently  the  case.  Care  must  be  taken  in  every  case 
that  the  dam  rests  throughout  its  length  on  the  same  stratum 
(good  dams  have  been  built  in  which  this  rule  is  not  followed), 
and  that  the  rock  bed  is  sound." 

These  remarks  apply  more  particularly  to  investigations  for 
larger  reservoirs  than  this  series  of  articles  is  designed  to  discuss 
in  detail,  but  for  the  smaller  works  the  method  of  investigation  is 
essentially  the  same.  It  is  necessary  to  ascertain  if  the  basin  will 
be  watertight  when  finished,  which  is  assured  if  the  bottom  is  of 
impervious  earth  or  rock  without  fissures  leading  the  water  under 
or  around  the  natural  and  artificial  walls  of  the  basin. 

That  even  the  smaller  works  cannot  always  be  designed  with 
absolute  certainty  as  regards  underlying  formations  is  shown  by 
the  experience  of  Mr.  S.  E.  Babcock  in  building  the  Beaver  Creek 
dam  of  the  Little  Falls,  X.  Y.,  Water- Works.  Figure  13  and  the 
following  description  of  the  work  have  been  prepared  from  Mr. 
Babcock's  report  on  this  dam.  The  creek  is  dammed  by  a  masonry 
structure  with  a  spillway  50  feet  wide,  and  forms  a  basin  of  0.75 
acre. 

"The  dam  is  6  feet  high;  the  south  abutment  of  the  dam  is 
formed  into  a  receiving  chamber  and  inlet  of  conduit  line,  which 
is  provided  with  a  screen  having  1-inch  apertures  and  with  a  mov- 
able inlet  weir,  which  may  be  raised  or  lowered  to  allow  any  quan- 
tity of  water,  from  one  gallon  to  the  capacity  of  the.  conduit,  to 
flow  into  the  chamber  and  thence  into  the  conduit;  the  saddle  of 
the  dam  is  2  feet  above  the  top  of  the  conduit,  and  it  matters  not 
how  high  the  water  may  be  in  Beaver  Creek,  the  head  on  the  con- 
duit can  never  be  more  than  a  fraction  over  the  static  head  of  2 
feet  for  which  it  is  designed.  There  is  also  a  provision  made  for 
flushing  the  pond  at  the  inlet  chamber  by  means  of  a  short  length 
of  14-inch  pipe  controlled  by  a  valve  situated  inside  of  the  inlet 
chamber  house,  together  with  a  6-inch  branch  to  flush  out  or  draw 
off  the  inlet  chamber.  Again,  the  pond  may  be  drawn  entirely 
dry  and  the  waters  of  the  stream  passed  through  a  30-inch  pipe 
let  into  the  center  of  the  stone  dam,  closed  by  a  plug  at  the  upper 
end,  provided  with  a  deadeye,  chain  and  ring,  to  which  a  watch 
tackle  may  be  fastened  and  the  plug  removed. 

"It  was  expected  to  find  a  water-tight  foundation  of  rock  very 
near  the  surface,  upon  which  to  start  the  stone  dam.  The  surface 
indications  on  both  sides  of  the  stream  showed  sand-rock  ledges. 


64  WATER-WORKS    MANUAL. 

Upon  making  the  necessary  excavations,  the  surface  rock  was 
found  to  be  very  seamy  and  loose  and  interspersed  with  a  hard- 
pan  formation.  It  was  necessary  to  go  down  about  9  feet,  as  oc- 
casion required,  to  obtain  a  water-tight  foundation,  entailing  an 
expense  of  over  $8,000  above  what  was  originally  calculated." 

One  of  the  most  surprising  cases  of  geological  conditions  in- 
fluencing reservoir   construction   is   afforded   by  the   Wentwood 
reservoir  of  the  Newport,  England,  Water- Works,  now  approach- 
ing completion.    In  the  fall  of  1892  the  Borough  Surveyor  made 
a  number  of  borings  on  the  site  of  the  proposed  reservoir,  and  re- 
ported the  ground  favorable  for  the  construction  of  a  suitable 
dam.     He  was  appointed  water  engineer,  and  with  expert  assist- 
ance prepared  plans  for  the  work.    A  contract  was  made  for  the 
construction  of  the  basin,  and  two  years  later  the  contractor  began 
the  excavation  of  the  puddle  trench.    After  going  down  some  100 
feet,  and  revealing  a  badly  fissured  sandstone  rock,  he  was  ordered 
to  suspend  work.     About  $250,000  had  been  spent  by  this  time. 
Mr.  G.  II.  Hill,  of  Manchester,  was  consulted,  and  he  reported 
that  a  geologist  should  be  retained  to  assist  him.    Mr.  Tiddernann 
was  appointed,  and  an  examination  of  the  problem  convinced 
him  the  reservoir  could  never  be  made  tight.     The  resident  en- 
gineer, who  was  a  geologist  as  well  as  an  engineer,  was  then  asked 
to  give  an  opinion  on  the  matter.    He  advised  making  some  prac- 
tical tests  of  the  site,  and  his  advice  was  followed.     Another 
geologist  was  then  retained,  who  reported  in  favor  of  carrying  out 
the  resident  engineer's  tests  and  continuing  construction  if  they 
gave  satisfactory  indications.     By  this  time,  so  much  conflicting 
advice  had  been  secured,  that  the  council  retained  Messrs.  Hill 
and  Hawksley  to  go  over  the  whole  evidence,  examine  the  site  and 
submit  a  comprehensive  report  on  the  subject.    They  carried  out 
many  tests,  made  examinations  and  reported  in  favor  of  totally 
abandoning  the  site.    Accordingly  the  contract  was  annulled  by 
paying  the  contractor  a  bonus  of  $50,000  in  addition  to  the  sum 
expended  on  account  of  actual  construction.     The  resident  en- 
gineer then  succeeding  in  persuading  the  authorities  to  authorize 
a  test  of  the  site  on  a  large  scale.  •  The  puddle  trench  was  filled 
with  water,  and  in  spite  of  the  fissures  and  clefts  in  the  rock  the 
experiment   was   a   highly   satisfactory   one.      Other   tests   gave 
equally  assuring  indications,  so  Mr.  Baldwin  Latham  was  retained 
to  examine  the  site.    His  report  was  so  favorable  that  the  authori- 


WATER-WORKS    MANUAL.  65 

ties  voted  to  resume  operations,  conducting  the  work  themselves, 
and  this  was  done  in  May,  1896. 

MATERIALS. 

There  is  little  to  be  said  concerning  the  materials  for  use  in  a 
masonry  dam,  other  than  they  must  give  a  tight  structure.  Stone 
varies  so  widely  in  its  character  that  it  would  be  a  waste  of  time  to 
enter  into  a  description  of  masonry  here.  What  particular  class 
to  use  in  any  case  naturally  is  governed  by  local  conditions.  In 
all  cases  the  masonry  must  unite  intimately  with  the  rock  bottom, 
and  must  be  carried  out  in  such  a  manner  that  it  is  certain  a  fairly 
homogeneous  mass  of  uniform  strength  has  been  constructed. 
Kranz  says  in  his  "Study  of  Eeservoir  Dams":  "The  union  on  all 
faces  and  beds  must  be  irregular  or  cyclopean.  There  should  be 
no  joints  in  the  entire  structure,  and  pains  must  be  taken  to  make 
the  dam  a  single  monolith.  Cyclopean  rubble  masonry  has  a  fur- 
ther advantage  in  that  it  can  be  easily  executed  to  any  section; 
the  most  complicated  curves  can  be  easily  marked  out  by  forms  or 
templets,  so  that  the  masonry  is  easily  and  quickly  carried  ahead, 
a  matter  of  no  small  importance." 

In  order  to  show  more  clearly  what  is  meant  by  the  term  "cy- 
clopean masonry,"  one  much  used  in  England,  but  not  employed 
here  to  any  extent,  the  work  on  three  dams  is  here  described,  the 
wording  of  the  engineer's  descriptions  being  given  in  two  cases, 
and  followed  very  closely  in  the  third. 

Manchester  Water-Works,  Thirlmere  dam,  George  Henry  Hill, 
Engineer. — "The  foundation  is  everywhere  sunk  into  the  solid 
rock,  and  at  the  river  reaches  a  maximum  depth  of  50  feet  below 
the  bed.  The  dam  is  constructed  of  concrete,  gauged  5  parts  of 
broken  stone  and  sand  to  1  of  cement;  large  blocks  of  rock  from 
one-half  to  four  tons  in  weight  being  imbedded  in  it  sufficiently 
far  apart  to  be  properly  surrounded  with  concrete.  These  blocks 
were  not  allowed  to  be  placed  within  about  7  feet  of  the  inner 
face.  All  the  fine  material  for  the  concrete  was  produced  by 
grinding  the  stone  of  the  district.  The  dam  is  faced  on  both 
sides  with  heavy  chisel  bedded  and  jointed  masonry  of  an  average 
thickness  of  about  2  feet,  well  bonded  into  the  concrete  of  the 
dam.  The  batter  on  the  lake  side  is  1^  inches  to  a  foot,  and  the 
outside  is  curved  to  a  radius  of  100  feet.  The  dam  is  finished  at 
the  top  of  the  outer  face  by  two  courses  of  ashlar  18  inches  thick, 


66  WATER-WORKS    MANUAL. 

and  on  the  inner  face  by  one  course  of  the  same  thickness.     The 
top  of  the  dam  carries  a  roadway  16  feet  wide." 

Vyrnwy  masonry  dam,,  George  F.  Deacon,  Engineer. — "The 
mortar  and  concrete  were  put  in  so  dry  that  considerable  ramming 
was  everywhere  necessary  to  produce  the  jelly-like  consistency 
which  betokens  incompressibility,  and  until  that  consistency  was 
everywhere  attained,  ramming  did  not  cease.  The  nibbing  of  the 
fine  portions  of  lime  or  cement  or  sand  into  the  interstices  of  the 
coarser  particles  during  the  shaking  and  subsequent  trembling  of 
the  whole  mass  under  the  rammer  cannot  be  attained  in  any  other 
way. 

"In  the  preparation  of  the  rock  foundation  all  dislocated  rock 
was  removed.  Where  long,  steep  slopes  occurred  in  the  sound 
rock  it  was  benched,  but  with  obtuse  inner  angles,  and  it  was  then 
rendered  scrupulously  clean  with  wire  brushes  and  jets  of  water 
under  pressure. 

"Over  the  irregular  surface  of  the  foundation  rock  thus  pre- 
pared a  good  coating  of  Portland  cement  mortar  was  brushed. 
Upon  this  the  work  was  raised,  in  hollow  places  too  small  for  large 
stones,  with  hand-set  stones  and  strong  mortar,  and  only  differed 
from  ordinary  rubble-work  in  the  greater  density  of  its  beds  and 
joints.  This  greater  density  was  secured  by  permitting  neither 
masons,  bricklayers  nor  trowels  to  appear  upon  any  part  of  the 
work  except  the  face,  and  by  substituting  for  them  men  not  too 
old  or  prejudiced  to  learn,  with  shovels,  mallets  and  numerous 
ramming  tools  of  different  sizes  and  shapes.  Whenever  spaces 
were  too  small  for  good-size  rubble-work,  they  were  filled  with 
mortar  into  which  macadam  size  broken  stone  was  rammed,  but 
no  previously  mixed  concrete  was  used.  When  a  sufficiently  large 
area  was  thus  secured  it  was  leveled  up  with  mortar,  among  which 
broken  stone  was  uniformly  scattered  from  shovels,  and  beaten  in 
with  a  flat  beater  formed  of  ^-inch  wrought-iron  plate  about  \ 
foot  square,  turned  up  J  inch  at  each  side  and  having  a  wooden 
spade-like  handle  inserted  in  a  wrought-iron  socket  riveted  to  the 
center  of  the  upper  side  of  the  plate.  The  work  was  thus  brought 
to  a  perfectly  level  surface  on  to  which  a  bed  of  mortar  about  2 
inches  thick  was  immediately  shoveled,  leveled  with  steel  brushes, 
and,  if  it  appeared  unduly  stiff,  beaten  with  the  same  flat  beater. 
Upon  this  a  large  stone  was  lowered  and  beaten  down  with  many 
heavy  two  handed  mallets  having  cylindrical  timber  heads  6  to  7 


WATER-WORKS    MANUAL.  67 

inches  in  diameter  and  14  inches  long.  The  effect  was  to  squeeze 
out  some  mortar,  even  from  under  the  largest  stones,  and  to 
cause  it  to  mount  in  the  joints  to  a  head  of  several  inches.  Into 
these  joints  mortar  and  broken  stone  was  packed  as  before,  and  if 
the  day's  work  was  nearly  completed  the  higher  portions  of  the 
joints  were  then  crammed  with  guano  bags  so  completely  that  to 
the  coming  rain,  frost,  or  sunshine  no  artificial  work  was  exposed. 
It  is  to  be  particularly  noted  that  toward  the  end  of  a  day's  work 
the  joints  were  never  allowed  to  be  more  than  half-filled  with 
mortar  or  concrete,  but  that  the  filling,  so  far  as  it  went,  was 
finally  finished  at  the  time  by  dint  of  firm  ramming  with  blunt 
ended  swords  and  ramming  tools  suitable  for  the  various  widths  of 
joints.  Thus,  when  the  work  was  resumed,  whether  a  single  night 
or  many  days  and  nights  had  intervened,  the  junction  between 
the  new  and  the  old  mortar  work  had  the  smallest  possible  area, 
and  had  been  thoroughly  protected  from  the  weather  in  the  in- 
terval/' 

In  order  to  reduce  the  hydrostatic  pressure  on  the  base,  due  to 
the  percolation  of  water  through  the  seams  of  the  rock,  along  the 
base  of  each  of  the  more  important  beds  of  rock,  not  within  15 
feet  of  the  face  of  the  dam,  a  drain  was  formed  in  the  masonry 
between  6  and  9  inches  square,  and  from  these  drains  funnels  were 
carried  up  in  different  vertical  transverse  planes  of  the  dam  to 
above  the  backwater  level.  The  funnels  all  issue  at  the  side  of  a 
longitudinal  tunnel  4|  feet  by  2%  feet,  so  that  the  flow  from  each 
is  rendered  visible.  From  this  tunnel  a  cross  tunnel  serves  as  an  on  t- 
let  for  the  water  from  the  rock  aad  as  a  passage  to  the  main  tunnel. 

Boyd's  Corner  dam,  J.  J.  E.  Croes,  M.  Am.  Soc.  C.  E.,  En- 
gineer in  Charge. — The  lower  portion  of  the  Boyd's  Corner  dam 
of  the  New  York  Water- Works  consists  of  concrete  in  which  large 
unworked  stones  were  laid,  while  in  the  upper  portion  concrete 
alone  was  used.  Above  the  bed-rock  the  concrete  is  faced  on  both 
sides  with  coursed  stone  having  cut  beds  and  joints.  The  mortar 
used  was  composed  of  one  part  of  hydraulic  cement  to  two  parts 
of  sand,  by  measure;  the  proportion  of  mortar  to  stone  was  such 
as  to  fill  all  void  spaces,  and  be  in  excess  of  the  latter  not  more 
than  10  per  cent.  The  concrete  was  laid  in  courses  of  6  inches 
and  well  rammed.  The  large,  rough  stones  were  laid  in  full  beds 
of  mortar,  and  their  surfaces  covered  with  mortar  half  an  incii 
thick  immediately  before  laying  concrete  around  them. 


68  WATER-WORKS    MANUAL. 

In  a  description  of  this  work  written  by  Mr.  Croes,  it  is  said  that 
from  the  beginning  to  the  end  of  the  construction  there  was  a 
continuous  struggle  on  the  part  of  the  engineers  to  have  the 
sand  for  the  mortar  properly  cleaned  and  screened,  and  of  the 
contractor  to  avoid  it.  Several  methods  of  washing  were  tried,  of 
which  the  most  successful  consisted  in  spreading  the  sand  in  a 
layer  of  about  3  inches  depth  on  the  bottom  of  a  shallow  box, 
6x12  feet,  slightly  inclined,  and  playing  on  it  with  a  hose  from  a 
force  pump.  In  freezing  weather  the  mortar  was  mixed  with  salt 
waterj  the  rule  for  the  preparation  of  the  brine  being  to  dissolve  1 
pound  of  rock  salt  in  18  gallons  of  water  when  the  temperature 
was  at  32°  Fahr.,  and  add  3  ounces  of  salt  for  3  degrees  lower 
temperature.  The  masonry  laid  with  mortar  thus  prepared  stood 
well,  and  showed  no  signs  of  having  been  affected  by  the  frost. 
The  experience  gained  on  this  work  indicates  that  it  does  not  pay 
to  use  large  blocks  of  stone,  when  the  thickness  of  the  dam  is  less 
than  about  10  feet. 

The  Sodom  Dam,  Alphonse  Fteley,  Chief  Engineer. — The  So- 
dom dam  of  the  Croton  Water- Works  is  regarded  as  a  remarkably 
tight  structure,  and  for  this  reason  the  following  notes  concern- 
ing its  construction  have  been  condensed  from  an  article  by  Mr. 
Walter  McCulloh,  M.  Am.  Soc.  C.  E.,  who  was  connected  with  the 
work  from  its  commencement. 

The  bed  of  the  river  was  prepared  by  blasting  with  light  charges 
of  40  and  60  per  cent,  dynamite  until  firm  rock  was  reached.  All 
loose  seams  were  followed  up  with  block  holes  and  black  powder 
blasting  and  by  barring  out  until  a  solid  and  practically  tight  bot- 
tom was  secured.  The  surface  prepared  in  this  manner  was  swept 
with  wire  stable  brooms  and  washed  clean  with  streams  from  hose 
pipes. 

When  the  bottom  was  ready,  it  was  decided  to  cover  it  with  rich 
Portland  cement  concrete  so  as  to  form  a  series  of  small  level  beds 
on  which  to  start  the  rubble  masonry.  This  plan  was  abandoned 
after  a  two  day's  trial,  because  it  was  found  a  better  bed  could  be 
made  with  a  rubble  of  small  stones.  "A  large  quantity  of  water 
made  its  way  through  the  loose  rock  above  the  bottom,  and  in 
many  places  through  seams  in  the  bottom  itself;  but  in  these  cases, 
where  the  rock  was  solid,  the  seams  were  not  followed  any  deeper. 
The  springs  in  the  bottom  would  wash  the  mortar  out  of  the  con- 
crete, and  in  many  cases  render  it  worthless;  but  in  making  the 


WATER-WORKS    MANUAL.  69 

rubble  beds,  the  water  could  be  led  round  and  prevented  from  do- 
ing harm.  These  streams  were  nursed  about  from  place  to  place 
till  finally  a  small  well,  2  feet  in  diameter  and  1  to  2  feet  deep, 
would  be  formed  just  around  the  point  where  the  water  boiled  up. 
When  the  mortar  about  each  little  well  had  thoroughly  set,  the 
water  was  bailed  out,  the  well  quickly  filled  with  dry  mortar,  a  bed 
of  stiff,  wet  mortar  put  on  top  of  this,  and  on  top  of  all  a  large 
rubble-stone  was  placed/'  It  will  be  noticed  that  the  principle 
governing  this  treatment  of  ground  water  is  the  exact  opposite  of 
that  of  the  method  of  Mr.  Deacon  on  the  Vyrnwy  dam,  which  is 
also  that  of  some  French  engineers;  that  is  to  say,  the  construction 
of  drains  through  the  masonry  to  take  away  the  water  from  the 
springs. 

The  rubble  masonry  laid  below  the  bottom  of  the  river  was  in  a 
2  to  1  Portland  cement  mortar.  Above  that  level,  on  the  up- 
stream face,  it  was  given  a  protection  of  facing-stone  30  inches 
deep,  and  also  above  the  level  of  the  ground  on  the  down-stream 
face.  The  rubble  backing  of  the  central  portion  of  the  wall  was 
laid  in  a  3  to  1  Portland  cement  mortar.  Rubble-stones  varied 
from  a  cubic  foot  to  a  cubic  yard  in  bulk,  and  in  placing  them  the 
beds  of  mortar  were  made  very  full,  and  the  stone  thoroughly 
shaken  io  a  firm  position.  The  rubble  was  not  carried  on  in  level 
courses,  but  was  broken  as  much  horizontally  as  possible,  so  as  to 
avoid  having  a  straight  joint  of  mortar  through  the  wall.  In  fill- 
ing the  interstices  the  rule  invariably  followed  was  to  put  the  mor- 
tar in  first,  then  force  into  it  all  the  spalls  it  would  take,  thus  in- 
suring perfectly  full  joints  and  as  much. stone  in  the  work  as  pos- 
sible. Grouting  was  not  permitted  at  all.  All  stones  of  what- 
ever size  were  thoroughly  washed  before  going  on  the  wall,  and 
were  usually  wet  when  placed  in  the  work.  The  rubble-stone  was 
a  hard  and  tight-grained  gneiss  of  irregular  cleavage,  obtained 
about  1|  miles  from  the  dam,  while  the  facing-stones  were  a  light 
limestone  obtained  7  miles  distant  at  a  quarry  opened  for  the  dam 
expressly. 

South ington,  Conn.,  Dam,  T.  H.  McKenzie,  Engineer. — The 
dam  of  the  distributing  reservoir  at  Southington  is  an  example  of 
masonry  structures  not  resting  on  rock.  "The  bed  of  the  stream 
was  a  quicksand,  which  lay  very  firmly  in  its  natural  bed.  The 
foundation  was  prepared  by  excavating  two  trenches  parallel  with 
the  face  of  the  dam  to  a  depth  of  about  3  feet.  Sills  were  laid  at 


70  WATER-WORKS    MANUAL. 

the  bottom  and  top  of  the  excavation  and  sheet  piling  driven 
down  and  spiked  to  the  sills.  The  trenches  were  then  filled  with 
concrete,  and  a  layer  of  concrete  1  foot  thick  by  15  feet  wide 
covers  the  entire  surface  under  the  dam.  The  dam  is  built  of 
granite  rubble  masonry.  The  stone  was  quarried  within  1,000 


FIGURE  14.— MASONRY  DAM  AT  SOUTHINGTON. 


feet  of  the  dam.  Every  stone  was  cleaned  and  wet  before  laying, 
and  was  laid  in  a  full  bed  of  cement-mortar;  all  interstices  were 
filled  with  mortar  and  stone  driven  into  it."  Figure  14  is  a  cross- 
section  of  the  dam  through  the  overflow. 

EARTH  BACKING. 

It  will  be  noticed  that  the  Southington  dam  has  an  earth  back- 
ing, a  feature  approved  by  some  engineers  and  condemned  by 
others.  One  of  the  most  striking  examples  of  such  construction 
is  the  Dunnings  dam  at  Scranton,  Pa.,  built  under  the  direction 
of  Mr.  E.  Sherman  Gould,  M.  Am.  Soc.  C.  E.  This  is  a  very  in- 
teresting structure  in  many  respects,  particularly  as  the  masonry 
dam  proper  rests  for  part  of  its  length  on  rock  and  for  the  remain- 
ing distance  on  "fine  sand  and  gravel,  quicksand  and  cobblestones 
— hard,  compact,  inelastic — a  natural  concrete  in  fact,"  into 
which  a  bar  could  not  be  forced  more  than  a  foot  or  so  by  working 


WATER-WORKS    MANUAL.  71 

or  driving.  The  whole  of  this  masonry  dam  is  backed  by  earth^ 
and  Mr.  Gould  gives  the  following  explanation  of  his  reason  for 
this  backing: 

-  "Had  the  inside  embankment  been  confined  to  the  northerly 
portion,  a  very  heavy  and  expensive  retaining  wall  projecting  into 
the  reservoir  would  have  been  needed,  costing  more  than  making 
the  bank  continuous.  A  second  reason  was  the  conviction  that 
such  a  backing  is  always  an  advantage,  even  to  a  masonry  dam. 
It  impedes  leakage  and  is  equivalent  to  a  deepening  of  the  founda- 
tion on  the  water  side.  A  dam  built  in  this  way  may  be  regard- 
ed as  an  earthen  dam  in  which  the  exterior  slope  of  earth  has  been 
replaced  by  an  equivalent  mass  of  masonry  applied  to  the  front  of 
the  center  wall.  This  is  the  form  of  dam  of  medium  height 
which  the  writer  would  always  recommend  when  a  rock  bottom 
can  be  found.  If  the  foundation  must  be  upon  earth  he  would 
hesitate  to  adopt  it,  for  he  would  consider  the  extra  concentration 
of  weight  on  a  smaller  surface  at  the  junction  of  the  two  different 
materials.,  masonry  and  earth,  as  disadvantageous,,  and,  besides, 
would  probably  feel  that  the  more  extended  earthen  bank  would 
be  needed  to  smother  down  any  percolations  from  under  the  cen- 
ter wall  which  might  otherwise  show  in  front  of  the  dam." 

Other  engineers  hold  an  exactly  opposite  opinion.  Mr.  James 
D.  Schuyler.  M.  Am.  Soc.  C.  E.,  in  describing  the  remarkable 
Sweetwater  dam,  built  by  him,  states:  "The  (proposed)  combina- 
tion of  earth  and  masonry  was  rejected,  as  it  seemed  to  the  writer 
that  water  was  sufficiently  heavy  for  the  masonry  wall  to  support 
without  adding  the  last  straw  on  the  camel's  back,  of  a  mass  of 
saturated  earth." 

Such  divergent  opinions  cannot  be  reconciled  easily,  yet  the 
writer  believes  that  both  views  are  largely  correct,  basing  hia 
opinion  on  the  following  reasoning:  Mr.  Desmond  FitzGerald,  M. 
Am.  Soc.  C.  E.,  has  shown  conclusively  by  some  careful  experi- 
ments on  one  of  the  best  earth  dams  ever  built,  that  the  earth  of 
such  a  dam  on  the  upstream  side  of  a  tight  masonry  core-wall  is 
well  saturated  with  water.  His  experiments  were  conducted  by 
means  of  a  series  of  open  vertical  tubes  sunk  in  a  line  across  the 
clam.  Water  rose  in  the  tubes  on  the  upstream  side  of  the  core 
nearly  to  the  level  of  that  in  the  reservoir,  while  on  the  other  side 
of  the  core  the  earth  was  practically  dry.  The  fact  that  the  earth 
was  so  saturated,  however,  does  not  necessarily  prove  that  the  dam 


72  WATER-WORKS    MANUAL. 

would  leak  if  the  masonry  were  replaced  by  good  puddle,  for  many 
all-earth  dams  are  as  tight  as  any  engineer  could  wish.  The  water 
may  be  in  part  of  the  earth,  yet  encounter  such  enormous  fric- 
lioual  resistance  in  passing  through  the  almost  microscopical  in- 
terstices in  a  well-built  bank  that  the  head  which  tends  to  force  it 
along  is  completely  frittered  away.  Consequently  it  is  believed 
that  where  a  comparatively  low  masonry  dam  is  built  on  a  rock 
bottom,  the  use  or  disuse  of  an  earth  fill  is  a  matter  of  local  con- 
ditions. If  it  is  cheaper  to  use  one  than  to  build  retaining  walls, 
as  in  the  case  of  the  Dunnings  dam,  the  writer  would  do  so,  pro- 
portioning the  masonry  to  carry  some  earth  pressure,  as  Mr.  Fitz- 
Gerald's  experiments  indicate  such  a  pressure  probably  would  ex- 
ist. If  the  earth  backing  would  add  expense  to  the  structure,  he 
certainly  would  not  use  it,  as  he  believes  a  sufficiently  safe  and  im- 
pervious dam  can  be  built  of  masonry  alone. 

The  Southington  dam,  however,  was  not  founded  on  rock  but 
on  a  firm  quicksand,  and  it  will  be  noticed  that  this  material  was 
disturbed  very  little  in  construction.  Why  an  earth  dam  was  not 
used  at  this  place  the  writer  is  unable  to  state,  although  he  has  no 
doubt  that  the  reason  was  simply  that  the  masonry  structure  was 
the  cheaper.  As  a  matter  of  fact,  many  low  masonry  dams  have 
been  built  on  earth  foundations,  and  have  given  good  satisfaction, 
particularly  on  Indian  irrigation  works.  A  backing  of  earth  on 
such  a  dam  is  not  necessary  in  the  writer's  opinion,  but  it  has  two 
advantages.  In  the  first  place,  it  adds  just  so  much  material  for 
the  water  to  pass  through  before  it  can  go  under  the  dam.  The 
earth  at  the  dam  has  been  more  or  less  disturbed  during  construc- 
tion, and  the  fill  above  it  increases  the  frictional  resistance  to  per- 
colation and  consequently  the  liability  to  leakage  at  the  weakest 
part  of  the  bottom.  In  the  second  place  the  earth  fill  probably 
tends  to  produce  a  more  satisfactory  distribution  of  pressure  on 
the  earth  bottom,  a  matter  of  no  consequence  with  a  rock  bed;  the 
mathematical  investigation  of  this  feature  involves  so  many  as- 
sumptions as  to  be  of  little  value,  but  the  writer  considers  that  the 
weight  of  backing  against  a  masonry  dam  must  tend,  under  cer- 
tain condition,  to  make  the  distribution  of  pressure  on  the  earth 
about  the  base  of  the  masonry  more  nearly  uniform  than  is  the 
case  where  there  is  no  backing.  With  good  hardpan  such  an 
argument  would  be  of  little  importance,  while  with  some  other 
classes  of  earth  foundations,  on  which  circumstances  might  com- 


WATER-WORKS    MANUAL.  73 

pel  the  construction  of  a  masonry  dam,  this  matter  would  prob- 
ably be  worth  consideration. 

DESIGN. 

The  design  of  a  low  masonry  dam  is  a  matter  calling  for  little  of 
the  skill  which  the  preparation  of  the  plans  of  a  high  dam  de- 
mands. Experience  has  practically  settled  on  the  form  shown  on 
the  left  in  Figure  14a  as  that  generally  useful  for  structures  up  to 
15  feet  high,  not  liable  to  be  overflowed,  and  built  in  places  where 
suitable  stone  is  cheap.  The  dam  should  not  be  much  narrower 
on  top  than  is  shown  in  the  cut,  unless  it  is  short  and  the  reservoir 
covers  a  small  area.  It  frequently  happens  that  the  upstream  face 


FIGURE  Ha.  -  TYPES  OF  SMALL  MASONRY  DAMS. 

of  the  dam  is  more  nearly  vertical  than  the  other,  as  is  the  case  of 
the  middle  structure  shown  in  Figure  14a. 

The  principles  governing  the  stability  of  such  a  structure  may 
be  best  indicated  by  examining  the  stability  of  the  dam  shown  on 
the  left  in  Figure  14a,  which  is  a  New  Jersey  structure. 

in  the  first  place  it  must  be  able  to  withstand  any  forces  which 
tend  to  slide  any  part  of  the  masonry  over  that  below  the  level  at 
which  the  tendency  to  slide  is  assumed  to  exist.  In  any  dam  of 
the  class  under  construction  such  a  danger  can  be  made  so  remote 
by  avoiding  all  through  joints  in  the  masonry  and  setting  the 
stones  in  good  hydraulic  mortar  that  it  is  unnecessary  to  investi- 
gate this  feature  farther. 

In  the  second  place,  the  greatest  pressure  per  square  inch  on  the 
masonry  dam  at  any  point  of  the  dam  must  not  exceed  a  certain 
amount,  usually  assumed  to  be  about  150  pounds.  This  feature 
is  the  governing  one  in  high  dams,  and  has  attracted  the  attention 


74  WATER-WORKS    MANUAL. 

of  some  of  the  ablest  theorists  among  engineers;  the  literature  on 
the  subject,  especially  in  French,  is  of  much  interest,  but  does  not 
need  discussion  in  this  connection,  other  than  that  given  in  a  fol- 
lowing paragraph. 

In  the  third  place,  the  dam  must  be  amply  strong  enough  to 
resist  any  tendency  to  overturn  at  the  base  or  any  higher  section. 
Through  the  center  of  gravity  of  the  portion  of  the  dam  above  the 
given  horizontal  section,  which  is  assumed  to  be  the  base  in  this 
case,  let  fall  a  vertical  line,  and  from  a  point  two-thirds  of  the  dis- 
tance from  the  high-water  level  to  the  given  horizontal  section, 
draw  a  line  perpendicular  to  the  face  of  the  dam.  Rules  for  find- 
ing the  center  of  gravity  of  a  plane  figure  are  given  in  Trautwine's 
"Handbook"  and  similar  works.  These  two  lines  will  intersect  at 
some  point,  0.  On  the  vertical  line  lay  off  0V  equal  to  the 
weight  in  pounds  of  so  much  of  a  vertical  slice  of  the  dam  1  foot 
thick  as  ILes  above  the  section,  and  on  the  second  line  lay  off  OP 
equal  to  the  hydrostatic  pressure  on  the  part  of  the  dam  under 
consideration.  This  pressure  is  31.2  times  the  square  of  the 
depth  of  water  in  feet.  These  two  distances  must  be  laid  off  to 
the  same  scale.  The  two  lines  are  the  sides  of  a  parallelogram,  of 
which  the  diagonal  OT  gives  the  direction  of  the  resultant  force 
acting  to  overturn  the  dam.,  the  point  X  at  which  the  line  of 
action  of  the  force  cuts  the  base  of  the  section,  and  the  magnitude 
of  the  force.  The  last  is  found  by  measuring  the  diagonal  with 
the  same  scale  used  in  laying  off  OP  and  0V.  Call  half  the  width 
of  the  horizontal  section  a,  and  let  the  distance  from  X  to  the 
middle  point  of  the  section  be  b;  the  factor  of  safety  of  the  wall  is 
equal  to  a  divided  by  b.  The  wall  is  not  secure  unless  this  factor 
of  safety  is  at  least  three,  but  in  most  masonry  dams  of  low  height 
it  is  generally  so  much  more  that  a  mere  glance  at  the  section  will 
convince  an  engineer  of  its  security.  In  the  figure,  the  factor  is 
about  eleven.  The  total  pressure  to  which  the  horizontal  section 
is  subjected  may  be  found  by  drawing  TA  perpendicular  to  0V 
and  measuring  OA  with  the  same  scale  used  in  laying  off  OP  and 
0  V.  Since  the  point  X  is  not  at  the  middle  of  the  horizontal  sec- 
tion, the  pressure  on  the  section  will  not  be  uniform,  but  will  be 
greater  at  F  than  at  B.  The  amount  of  this  maximum  pressure 
may  be  found  by  means  of  the  following  equation: 


- !) 


WATER-WORKS    MANUAL.  75 

In  this  equation  C  is  the  maximum  pressure  in  pounds  per  square 
foot,  D  is  the  total  pressure  in  pounds  on  the  base,  as  found  by 
measuring  the  line  OA,  b  is  the  width  in  feet  of  the  section  BF, 
and  t  is  the  distance  XF  in  feet.  This  method  of  finding  the 
.maximum  pressure  must  only  be  used  when  FX  is  greater  than 
one-third  BF  and  less  than  two-thirds  BF.  If  this  condition  is 
not  fulfilled  something  is  wrong  with  the  design  and  it  should  be 
changed. 

A  study  of  this  graphical  process  of  ascertaining  the  stresses  of 
a  dam  will  show  clearly  the  effect  of  changing  the  cross-section 
of  the  dam.  If  the  back  of  the  wall  on  which  the  water  presses 
were  vertical,,  the  center  of  gravity  of  the  masonry  would  be 
thrown  toward  B,  while  if  the  dam  were  made  thinner  at  the  same 
time  the  ratio  of  FX  to  FB  could  be  maintained  constant.  It 
might  seem  a  good  plan  to  do  this,  but  a  moment's  reflection  will 
show  that  a  dam  has  other  forces  to  resist  beside  hydrostatic  press 
ure;  it  must  be  able  to  withstand  the  pressure  of  ice  and  possibly 
the  passage  of  ice  and  drift  over  its  crest  in  floods.  Mathematics 
offer  slight  assistance  in  estimating  the  stresses  such  forces  exert 
on  a  low  dam,  and  experience  is  the  best  teacher  in  such  matters. 
In  the  case  of  the  dam  shown  on  the  left  in  Figure  14a,  it  is  un- 
necessary to  investigate  the  security  of  the  structure  when  the 
reservoir  is  empty,  but  in  most  cases  this  should  be  done. 

The  middle  cut  in  Figure  14a  shows  the  cross-section  of  a  low 
masonry  dam  designed  by  Mr.  John  W.  Hill,  M.  Am.  Soc.  C.  E., 
for  the  Findlay,  0.,  water-works.  This  structure  is  made  very 
heavy  to  withstand  the  floods  which  are  liable  to  submerge  it  10 
or  more  feet,  and  affords  an  example  of  a  structure  of  about 
the  maximum  security,  too  heavy  indeed  for  ordinary  pur- 
poses. It  is  of  interest  in  this  connection,  however,  as  il- 
lustrating the  use  of  steps  on  the  down-stream  face  of  a 
dam.  These  steps  break  the  force  of  the  water  passing  over 
the  crest  of  the  dam  and  prevent  the  wearing  away  of  the 
bedrock  on  which  the  water  strikes.  Unless  this  bedrock 
is  an  exceptionally  hard  stone  it  is  best  to  break  the  fall  of  the 
water  by  steps  every  few  feet,  or  else  give  the  face  of  the  dam  a  re- 
versed curve  such  that  the  water  will  tend  to  leave  the  masonry 
of  the  structure  at  only  a  small  angle  with  the  river  bed.  Aprons 
of  timber  or  stone  blocks  are  generally  used  below  a  dam  to  pro- 
tect the  bedrock,  although  they  are  sometimes  replaced,  as  shown 


76  WATER-WORKS    MANUAL. 

in  the  section  on  the  right  in  Figure  14a,  by  a  water  cushion,  or 
pool  of  water  formed  by  a  small  secondary  dam  a  short  distance 
below  the  main  structure. 

This  dam  was  built  by  Mr.  J.  W.  Ledoux,  M.  Am.  Soc.  C.  E., 
for  the  water-works  of  Greenville,  S.  C.,  and  may  be  taken  as  typi- 
cal of  small  curved  dams.  The  dam  forms  a  reservoir  in  which  is 
impounded  the  water  from  a  catchment  area  of  about  1  square 
mile  of  densely  wooded  mountainous  country.  The  masonry  is 
granite  rubble  laid  in  a  mortar  composed  of  one  part  of  hydraulic 
cement  to  two  parts  of  sand.  The  stone  was  taken  from  a  ledge 
400  feet  upstream  and  hauled  on  a  tramway  from  two  derricks  at 
the  quarry  to  two  on  the  dam.  The  cement  cost  $1.64  on  the  cars 
and  was  hauled  3-J  miles  in  carts,  and  the  sand  1  mile  over  ordi- 
nary country  roads.  Each  cubic  yard  of  mansonry  required  1.4 
barrels  of  cement.  The  masons  were  paid  $3  on  an  average  and 
common  laborers  $1  a  day.  The  masonry  cost  $6.50  a  cubic  yard 
exclusive  of  the  coping. 

SPECIFICATIONS. 

Something  should  be  said  concerning  the  specifications  for 
stone  dams,  as  there  is  a  tendency  to  make  them  very  elaborate 
even  when  the  structure  is  a  small  one.  It  is  now  pretty  well 
recognized  that  specifications  for  such  dams  must  be  general  and 
refer  the  contractor  to  the  engineer  for  his  detailed  information, 
rather  than  be  minutely  detailed.  In  the  matter  of  cement,  for 
example,  some  of  the  most  important  recent  work  of  this  class  has 
been  let  under  specifications  which  are  without  any  of  the  exact 
requirements  considered  necessary  in  masonry  work  for  some 
other  purposes.  Mr.  A.  Fteley,  for  example,  wrote  the  following 
specification  for  the  Titicus  dam  of  the  Croton  water-works,  and 
practically  the  same  wording  is  used  in  a  recent  Boston  specifica- 
tion: 

"American  cement  and  Portland  cement  are  to  be  used.  The 
American  cement  must  be  in  good  condition  and  must  be  equal  in 
quality  to  the  best  Kosendale  cement.  It  must  be  made  by  manu- 
facturers of  established  reputation,  must  be  fresh  and  very  fine 
ground,  and  in  well-made  casks  (or  equally  safe  and  tight  recep- 
tacles approved  by  the  Engineer).  The  Portland  cement  must  be 
of  a  brand  equal  in  quality  to  the  best  English  Portland  cement. 
To  insure  its  good  quality,  all  the  cement  furnished  by  the  con- 
tractors will  be  subject  to  inspection  and  rigorous  tests;  and  if 


WATER-WORKS    MANUAL.  77 

found  of  improper  quality,  will  be  branded,  and  must  be  imme- 
diately removed  from  the  work,  the  character  of  the  tests  to  be 
determined  by  the  Engineer." 

These  requirements  throw  the  whole  responsibility  of  the  char- 
acter of  the  cement  on  the  engineer,  and  enable  him  to  reject 
poor  cements  which  he  might  be  forced  to  accept  if  this  material 
were  supplied  under  the  more  elaborate  requirements  in  favor 
until  recently.  Elaborate  cement  specifications  are  of  value  in 
certain  works,  but  the  prevailing  opinion  is  that  they  are  not 
adapted  for  securing  the  most  satisfactory  construction  of  dams. 

The  rubble  backing  of  a  small  masonry  dam  at  Skaneateles 
Lake  was  built  according  to  the  following  specifications: 

"The  backing  stones  of  the  dam shall  be  of 

sound,  well-shaped  and  durable  stones,  and  in  general  not  less 
than  6  inches  in  thickness,  nor  less  than  3  feet  area  of  bed.  The 
edges  of  all  thin  wedge-shaped  stones,  before  they  are  placed  in 
the  work,  must  be  broken  off  to  a  thickness  of  6  inches  or  more. 
The  hearting  stones  shall  be  laid  on  their  broadest  beds,  and  laid 
so  that  no  two  vertical  joints  shall  be  opposite,  or  in  a  position  to 
form  a  straight  line  through  the  wall.  No  pinning,  wedging  or 
leveling  up  with  spalls  that  shall  raise  the  stones  from  their  beds 
will  be  permitted.  No  joints  or  spaces  between  stones  will  be 
permitted  to  be  filled  with  spalls  until  after  the  mortar  is  in  and 
completely  fills  the  space;  then  thin  pieces  of  stones  or  spalls  will 
be  gently  driven  in.  All  the  masonry  shall  be  laid  in  full  beds 
of  mortar  and  the  joints  shall  be  flushed  full  to  the  top  as  soon  as 
the  stone  is  placed.  No  grouting  will  be  permitted.  ]STo  mov- 
ing, dressing  or  hammering  of  the  stone  on  the  wall,  that  will 
disturb  the  setting  of  the  cement,  will  be  allowed." 

The  facing  stones  of  the  dam  have  to  be  provided  for  more 
definitely.  In  the  case  of  the  masonry  dam  of  Reservoir  No.  5  of 
the  Boston  Water- Works,  now  a  part  of  the  Metropolitan  system, 
the  specification  reads: 

"The  outer  faces  of  the  masonry  dam are  to  be 

made  of  range  stones of  unobjectionable  quality, 

sound  and  durable,  free  from  all  seams  and  other  defects,  and  of 
such  kind  as  shall  be  approved  by  the  Engineer.  All  beds,  build? . 
and  joints  are  to  be  cut  true  to  a  depth  of  not  more  than  4  inches 
and  not  less  than  3  inches  from  the  faces,  and  to  surfaces  allow- 
ing of  one-half  inch  joints  at  most;  the  joints  for  the  remaining 


78  WATER-WORKS   .MANUAL. 

part  of  the  stones  not  to  exceed  2  inches  in  thickness  at  an}' 
point." 

This  dam  is  a  fairly  large  structure.,  and  the  specifications  for 
face  stones  for  it  correspond  with  those  for  similar  works  on  the 
Croton  water  system  of  New  York.  It  should  be  stated,  how- 
ever, that  many  engineers  prefer  more  stringent  requirements  for 
facing  masonry,  and  an  example  is  given  in  the  following  extract 
from  the  specifications  for  a  dam  at  Skaneateles  Lake,  already 
quoted: 

"The  face  of  the  masonry  in  the  dam  is  to  -be  of  a  heavy  class 
of  broken  range  ashlar,  having  horizontal  beds  and  vertical  joints, 
to  be  dressed  to  form  a  mortar  joint  not  exceeding  one-half  inch 
in  thickness  for  a  depth  back  from  the  face  of  the  wall  of  not  less 
than  10  inches  on  the  beds,  nor  less  than  6  inches  at  the  end 
joints.  The  stones  for  the  face  of  the  wall  must  generally  be  not 
less  than  10  inches  thick,  nor  less  than  2J  feet  long  in  line  of  the 
wall,  nor  of  a  less  width  of  bed  for  stretchers  than  12  inches,  and 
in  no  case  less  than  1J  times  the  depth  of  the  stone.  The  bond 
of  the  face  stones  in  general  shall  be  not  less  than  10  inches  and 
in  no  case  less  than  9  inches  with  each  other,  or  9  inches  with  the 
backing.  In  forming  the  bond  between  adjoining  face  stones  of 
varying  thickness,  properly  prepared  levelers  not  less  than  4 
inches  in  thickness  may  be  used,  but  where  a  difference  of  level 
of  less  than  4  inches  occurs,  the  bonds  shall  be  made  by  cutting 
a  check  in  the  stone.  Headers  occupying  at  least  one-fifth  of  the 
face  of  the  wall,  to  be  not  less  than  18  inches  wide  or  10  inches  in 
depth,  on  the  face,  and  in  general  not  less  than  3  nor  more  than 
3J  feet  long,  shall  be  placed  in  front  and  rear  of  the  wall,  so  that 
those  in  the  rear  shall  be  intermediate  to  those  in  front.  All 
face  stone  shall  be  laid  on  their  quarry  beds." 

The  specifications  for  masonry  dams  should  also  contain  the 
usual  clauses  for  insuring  good  materials  and  workmanship,  which 
it  is  unnecessary  to  outline  here.  '  The  best  drawn  specifications 
will  not  insure  a  good  structure  unless  the  work  is  done  under  the 
constant  supervision  of  a  competent  man  with  sufficient  authority 
to  prevent  any  poor  work  being  done.  Thorough  inspection  is 
the  secret  of  good  work  of  this  class,  and  such  inspection  cannot 
be  done  properly  by  anyone  who  is  not  perfectly  familiar  with  the 
laying  of  first-class  masonry.  The  writer  is  strongly  of  the 
opinion  that  masonry  dams,  small  or  large,  should  never  be  built 


WATER-WORKS   MANUAL.  79 

except  under  the  constant  supervision  of  such  a  man.  The  so- 
called  inspection  performed  by  instrumentmen  or  draftsmen  not 
needed  elsewhere  will  be  of  little  value. 

ROCK-FILL  DAMS. 

A  type  of  dam  which  has  been  used  extensively  in  the  West  is 
made  of  loose  rock  and  has  received  the  name  of  rock-fill.  Its 
origin  was  probably  a  loosely  built  timber  dam  in  which  the  tim- 
bering manifestly  added  little  if  anything  to  the  security  of  the 
structure.  It  was  but  a  step  from  such  a  dam  to  one  built  wholly 
of  loose  rock,  and  the  iconoclastic  engineers  who  constructed  the 
earlier  works  in  the  new  States  and  Territories  evidently  found  it 
an  easy  one  to  take.  The  fact  that  some  missteps  were  taken  at 
the  same  time  should  not  be  considered  as  totally  condemning 
their  whole  course  in  the  matter.  Sometimes  they  combined  the 
crib  and  rock-fill  constructions  in  one  dam,  like  the  Bowman  dam 
in  California.  In  this  case  a  crib  dam  was  built  first  and  then  the 
height  raised  to  twice  the  original  level  by  means  of  carefully 
placed  loose  stones  on  the  down-stream  side  and  on  top  of  the 
timber  work.  The  structure  is  about  100  feet  high  and  is  faced 
with  plank  like  most  of  its  type. 

Mining  dams  have  often  been  built  without  any  cribwork  what- 
ever. The  Fordyce  dam  in  California,  for  example,  is  about  70 
feet  high  with  an  upstream  batter  of  1  on  1  and  a  downstream 
batter  of  4  on  1.  It  is  90  feet  wide  at  the  bottom,  6  feet  on  top, 
and  consists  of  an  interior  mass  of  loose  stones  with  carefully 
placed  stones  on  each  face,  the  upstream  face  being  rendered 
tight  by  3-inch  plank.  In  a  few  cases  successful  attempts  have 
been  made  to  render  such  dams  water-tight  by  placing  an  earth 
bank  on  their  upstream  face;  the  dams  on  the  Pecos  and  Boise 
irrigation  systems  are  examples  of  such  construction. 

In  all  these  structures  the  purpose  of  the  rock  is  simply  to  give 
weight,  the  tightness  of  the  dam  depending  on  the  facing.  It  is 
evident  that  if  the  facing  gives  way  when  the  reservoir  is  full, 
there  is  a  strong  probability  that  the  stones  will  be  washed  away 
and  the  valley  below  flooded.  This  has  happened  several  times, 
and  it  is  therefore  advisable  to  construct  such  rock-fill  dams  only 
at  such  sites  as  render  it  certain  no  harm  will  be  done  farther 
down  the  valley  in  case  the  structures  fail.  In  their  proper  place, 
however,  these  dams  give  good  satisfaction. 


80  WATER-WORKS    MANUAL. 

Rock-fill  clams  formerly  cost  from  $2  to  $3  per  cubic  yard,  but 
modern  machinery  and  methods  have  reduced  these  figures  very 
much.  Mr.  11.  B.  Stanton,  M.  Am.  Soc.  C.  E.,  has  given  the  fol- 
lowing data  as  to  the  cost  per  cubic  yard  of  the  items  of  a  dam  of 
this  type.  Quarrying  rock,  6  cents;  loading  buckets  by  hand,  in- 
cluding breaking  large  rocks  with  powder,  20  cents;  hoisting  and 
conveying  rock,  6  cents;  placing  rock  on  dam,  3  cents;  cost  of 
plant,  10  cents;  total  cost,  45  cents;  common  labor  was  paid  $1.75 
a  day  and  coal  cost  $10  a  ton.  The  plant  consisted  of  one  Lidger- 
wood  cableway  with  three  derricks  on  the  dam  for  distributing 
and  placing  rock.  Quarrying  was  done  by  exploding  several  tons 
of  powder  in  drifts  and  shafts,  thus  breaking  up  from  25,000  to 
30,000  cubic  yards  of  rock  in  one  shot.  The  total  amount  of 
rock  in  the  dam  was  about  120,000  cubic  yards. 


CHAPTER  VI.— SPECIAL   FEATURES   OF   RIVER    AND 
POND   SUPPLIES. 

Irrigation  enterprises  have  furnished  many  valuable  precedents 
for  the  construction  of  water-works  for  domestic  supplies,  and 
among  these  are  various  provisions  for  removing  sand  and  sedi- 
ment from  the  water  of  the  streams.  Where  a  valley  is  crossed 
by  a  dam  forming  a  basin  of  such  size  that  the  water  within  it  has 
practically  no  current,  the  tendency  is  for  all  the  suspended  ma- 
terial in  the  water  to  sink  to  the  bottom.  In  such  a  case,  no  pro- 
vision has  to  be  made  for  the  removal  of  sand  from  the  water, 
since  it  has  probably  been  deposited  long  before  the  water  reaches 
the  intake.  In  other  cases,  the  stream  is  large  and  its  current  so 
slow  that  little  sand  is  held  by  the  water,  and  it  is  only  necessary 
to  lay  a  suction  main  out  into  the  river  and  pump  the  water 
needed.  In  still  other  cases,  the  stream  is  a  swift  mountain  river, 
full  of  sand  and  small  gravel,  especially  in  times  of  flood.  If  this 
material  is  admitted  to  the  conduit,  it  will  erode  it  rapidly  and 
cause  much  damage  at  the  gates  and  other  specials,  besides  tend- 
ing to  clog  the  pipes  at  every  low  point  on  the  profile.  It  fre- 
quently happens  the  river  is  so  large  that  only  a  low  weir  is 
needed  to  ensure  an  ample  supply  for  the  conduit  at  all  times, 
and  the  surplus  flows  over  the  weir  along  the  old  course  of  the 
river.  It  is  usual  to  have  a  spillway  on  these  weirs,  but  they  are 
often  inadequate  to  pass  the  full  flood  volumes. 

The  conditions  governing  the  design  of  headworks  to  intercept 
the  water  of  a  sediment-bearing  stream  have  been  stated  very 
fully  by  Mr.  William  Ham.  Hall,  M.  Am.  Soc.  C.  E.,  as  follows: 
"(1)  to  interpose,  in  the  form  of  a  dam  across  the  river  canyon  as 
little  obstruction  to  the  free  flow  of  its  high  floods  as  possible;  (2) 
to  keep  the  ordinary  flood  and  low-water  flow  of  the  stream  per- 
manently in  a  channel  next  to  the  intake:  C3)  to  prevent  the 
lodgment  and  accumulation  of  detritus  at  or  immediately  above 
or  below  the  intake;  (4)  to  draw  the  clearest  available  waters  into 


82  WATER-WORKS    MANUAL. 

the  canal  heading;  (5)  to  sluice  the  heavier  detritus  and  more 
heavily  laden  waters  rapidly  by  the  same."  In  order  to  fulfill 
these  conditions  Mr.  Hall  advises  the  adoption  of  two  features  in 
the  plans  wherever  practicable.  The  first  of  these  is  taking  water 
for  the  main  conduit  from  the  surface  of  the  natural  stream,  in 
a  thin  sheet  over  the  lip  of  a  long  weir,  and  with  the  least  possi- 
ble deflection  of  the  line  of  flow — that  is  to  say,  by  making  the 
weir  as  nearly  parallel  as  possible  to  the  direction  of  the  current. 
The  second  feature  is  flushing  away  the  waste  water  at  the  bot- 
tom, not  top,  of  the  waste  weir  and  giving  it  a  high  velocity  by 
sloping  the  channel  leading  to  the  sluice  gates.  "An  underflow 
gate  draws  from  the  bottom  of  the  stream  and  is  therefore  the 
proper  design  for  a  sluiceway  to  get  rid  of  the  sands  and  gravels 
carried  near  or  rolled  along  the  bottom.  It  should  not  be  used 
for  an  intake,  for,  thus  used,  it  directly  defeats  one  of  the  primary 
objects  desired.  Overflow  gates,  usually  put  in  as  flash-boards, 
can  be  designed  so  as  to  admit  of  handling  with  perfect  ease  un- 
der any  circumstances.  They  draw  from  the  top  of  the  stream 
first,  and  heavier  detritus  has  to  accumulate  before  passing  over 
them.  They  are,  for  this  reason,  detrimental  in  a  by-pass  sluice- 
way, but  exactly  applicable  for  intake  gateways;  and,  where  the 
waters  are  carrying  sediments,  the  intake  should  be  in  a  thin 
sheet  over  such  gates,  so  as  to  draw  only  from  the  surface  of  the 
natural  stream." 

Another  method  of  accomplishing  the  same  object  has  been 
described  by  Mr.  L.  L.  Tribus,  M.  Am.  Soc.  C.  E.  The  plan  was 
to  take  water  from  the  river  in  a  sheet  2  inches  thick  and  about 
100  feet  long.  The  water  passed  in  this  way  into  a  chamber  from 
which  it  flowed  under  a  suspended  apron  into  another  chamber, 
where  it  rose  and  finally  escaped  over  a  second  weir.  This  plan 
provided  for  the  withdrawal  of  the  clearest  water  in  the  stream, 
and  its  circuitous  flow  at  a  very  low  velocity  to  the  beginning  of 
the  conduit,  conditions  favorable  to  the  further  clarification  of 
the  supply  by  sedimentation.  Theoretically  the  transporting 
power  of  a  stream  varies  as  the  sixth  power  of  its  velocity,  and  al- 
though the  theoretical  conditions  are  never  realized,  it  is  fortu- 
nately true,  speaking  generally,  that  sedimentation  proceeds  more 
rapidly  than  the  simple  decrease  in  velocity  of  a  current.  Ad- 
vantage is  taken  of  this  fact  in  the  construction  of  sand  pits  along 
the  line  of  open  conduits,  as  will  be  pointed  out  later,  and  Eng- 


WATER-WORKS  MANUAL.  83 

lish  engineers  make  use  of  the  same  principle  in  designing  what 
they  call  residuum  lodges,  small  tanks  or  basins  at  the  upper  ends 
of  reservoirs  in  which  silt  or  other  sediment  is  removed  from  the 
water  of  feeders  before  it  enters  the  reservoirs  proper. 

The  use  of  lakes  and  ponds  as  sources  of  supply  requires  more 
skill  in  the  original  design  and  subsequent  operation  of  water- 
works than  would  at  first  seem  necessary.  The  reason  for  this  is 
to  be  found  in  the  phenomena  caused  by  the  changes  in  tempera- 
ture of  the  water,  which  have  been  studied  carefully  by  Messrs 
F.  P.  Stearns  and  Desmond  FitzGerald  and  should  be  understood 
by  the  manager  of  every  water  system. 

In  ponds  less  than  about  25  feet  in  depth  there  is  not  much 
more  than  5  or  6  degrees  difference  in  the  temperature  of  the  top 
and  bottom  layers  of  water,  but  in  deeper  ponds,  where  the  wind 
cannot  stir  up  the  whole  of  the  water,  a  different  condition  exists. 
To  understand  what  takes  place  it  must  be  recalled  that  water  is 
densest,  or  weighs  most  per  cubic  foot,  when  its  temperature  is 
39.2  degrees.  In  the  winter  the  natural  tendency  is  to  have  the 
bottom  layers  in  a  deep  pond  of  about  this  temperature,  and  the 
ascending  layers  more  and  more  cold  until  the  water  just  below 
the  ice  is  practically  at  the  freezing  point.  This  condition  re- 
mains until  the  ice  melts  in  the  spring,  when  the  surface  water 
is  warmed  and  consequently  becomes  more  dense.  Under  the  in- 
fluence of  the  increasing  warmth  and  winds  the  layers  change 
their  positions  until  finally  the  whole  volume  of  water  has  a  prac- 
tically uniform  temperature  and  is  consequently  in  a  condition 
of  unstable  equilibrium. 

As  the  season  progresses,  however,  the  top  layers  of  the  lake 
are  heated  a  few  degrees  above  those  below,  and  another  state  of 
stable  equilibrium  ensues,  with  the  coldest  water  at  the  bottom, 
the  contrary  of  the  case  in  winter.  During  the  summer,  the 
layers  more  than  about  15  feet  below  the  surface  are  stagnant  and 
unaffected  by  the  wind.  As  autumn  passes,  the  surface  water 
cools  and  a  reversal  of  the  conditions  in  the  spring  occurs,  result- 
ing in  another  state  of  unstable  equilibrium,  when  the  entire  con- 
tents of  the  pond  or  lake  are  turned  over. 

The  effect  of  these  phenomena  has  been  stated  generally  by  Mr. 
FitzGerald  in  the  following  words:  "In  a  lake  with  any  consider- 
able amount  of  organic  matter  in  it  and  also  in  deep  artificial 
storage  reservoirs,  where  the  surface  has  not  been  stripped,  the 


84  WATER-WORKS    MANUAL. 

lower  layers,  which  are  quiescent  during  the  great  stagnation 
period,  gradually  collect  all  the  organic  matter  from  the  upper 
layers,  and  decay  goes  on  until  the  oxygen  is  used  up.  The  water 
becomes  darker  and  darker,  until  by  October  it  is  very  yellow  and 
generally  has  a  disagreeable  smell.  Of  course,  when  the  great 
overturning  comes,  in  November,  all  this  bad  water  is  brought  to 
the  surface,  and  the  infusoria  and  diatoms  begin  to  grow  in  enor- 
mous numbers,  because  the  organic  matter  and  oxygen  are 
brought  together  and  provide  food  for  organic  life.  The  same 
phenomenon  takes  place  in  the  spring  period  of  circulation,  al- 
though on  a  smaller  scale."  Two  important  practical  lessons 
which  these  phenomena  teach  are  the  following: 

1.  In  drawing  water  for  use  from  a  deep  pond  or  reservoir  dur- 
ing the  two  periods  of  stagnation,  it  is  desirable  to  take  water 
from  near  the  surface,  and  if  there  is  a  surplus  in  the  basin,  to 
waste  the  bottom  layers,  which  contain  the  most  impurities,  so 
that  it  will  not  be  mixed  with  the  better  water  during  the  next 
overturning. 

2.  "Many  engineers  are  disposed  to  sneer  at  the  idea  of  the 
necessity  for  removing  all  the  organic  matter  from  the  bottom 
and  sides  of  the  valley  which  is  to  form  a  storage  basin  for  a  do- 
mestic supply.    There  is  a  marked  difference  in  the  condition  of 
the  water  below  the  20-foot  line  in  the  summer  in  a  properly  pre- 
pared basin  and  one  that  is  not  treated.     In  the  basins  on  the 
Boston  Water- Works  which  have  been  stripped  of  loam,  stumps, 
etc.,  and  have  had  their  shallow  fiowage  removed,  the  water  is 
comparatively  good  all  the  way  to  the  bottom,  even  in  October, 
when  the  effects  of  a  long  period  of  stagnation  are  best  studied. 
Oxygen  is  present,  showing  that  there  is  not  enough  organic  mat- 
ter present  in  a  state  of  decomposition  to  use  up  the  oxygen,  the 
organisms  are  few,  because  there  is  not  sufficient  food  to  support 
large  growths,  and  the  amorphous  matter  is  small  in  amount.    In 
a  sheet  of  water  not  so  treated,  however,  we  find  a  very  different 
condition  of  affairs.     There  is  no  oxygen  at  the  bottom,  a  high 
color,  much  organic  matter  (where  decay  has  been  arrested  from 
a  lack  of  oxygen),  and  a  considerable  amount  of  amorphous  mat- 
ter.    All  of  these  objectionable   characteristics  are   distributed 
throughout  the  whole  vertical  section  on  the  overturning,  in 
November,  resulting  in  large  growths  of  diatoms  and  infusoria. 
It  is  no  wonder  that  the  water  occasionally  tastes  bad  under  these 


WATER-WORKS   MANUAL.  85 

circumstances/''  (Extract  from  a  report  by  Mr.  FitzGerald,  dated 
January  1,  1895.) 

As  this  is  an  important  matter  to  the  owners  of  every  water- 
works drawing  its  supply  from  a  pond  or  lake  of  any  size,  a  brief 
resume  will  be  given  of  the  results  of  Mr.  Stearns'  investigations 
of  another  phase  of  this  subject,  which  were  made  with  much 
care.  It  is  of  course  necessary  for  all  organisms  to  have  food, 
which,  in  the  case  of  the  low  forms  of  plant  and  animal  life  in 
ponds  and  lakes  comes  either  from  sewage  and  manures  or  from 
the  vegetable  matter  in  the  bottom  of  the  basin.  Even  if  sewage 
is  turned  into  a  cesspool  and  filters  a  long  distance  through  the 
ground,  it  will  still  contain  a  large  amount  of  food  material  for 
the  organisms,  and  may  have  nearly  the  same  effect  in  promoting 
their  growth  as  it  would  had  it  been  turned  directly  into  the 
water.  The  second  source  from  which  this  food  may  be  derived, 
the  vegetable  matter  at  the  bottom  of  the  pond,  is  shown  in  the 
case  of  the  Ludlow  Eeservoir,  near  Springfield,  Mass.  The 
amount  of  food  material  in  the  water  in  summer,  when  the 
growth  of  algae  was  greatest,  was  three  times  that  of  the  winter. 
The  water  in  the  feeders  entering  the  reservoir  contains  little  of 
this  material,  which  points  to  the  bottom  as  the  source  of  the 
supply.  "With  regard  to  the  depth  and  size  and  absence  of  very 
shallow  flowage,  this  reservoir  ranks  high  among  those  of  the 
State.  As  a  further  indication  that  depth  is  less  important  than 
the  food  supply,  the  case  of  Filling's  Pond,  in  Lynnfield,  may  be 
cited.  This  is  a  very  old  storage  reservoir,  made  for  mill  pur- 
poses by  flowing  a  large  level  meadow  to  a"  depth  of  4  feet.  The 
average  depth  of  the  pond,  including  the  shallow  portions  near 
the  edges,  is  about  3  feet.  At  the  time  of  the  examination  it  was 
kept  constantly  full.  The  area  of  the  pond  is  in  the  neighbor- 
hood of  85  acres.  Examinations  made  during  the  summer  of 
1889  showed  that,  notwithstanding  the  small  depth  and  the  con- 
sequent high  temperature  of  the  water,  which  at  times  reached 
80°  Fahr.,  the  water  did  not  contain  any  abnormal  growth  of 
organisms  nor  become  offensive.  This  comparative  favorable  re- 
sult appears  to  be  due  to  the  fact  that  the  reservoir  is  so  old  that 
the  available  food  supply  has  been  removed  from  the  bottom/7 

In  this  connection  it  may  be  added  that  a  number  of  experi- 
enced engineers  have  reported  in  favor  of  a  thick  gravel  filling  on 
top  of  the  muck  or  peat  at  the  bottom  of  proposed  reservoirs, 


86  WATER-WORK^    MANUAL. 

where  the  cost  of  removing  the  vegetable  matter  was  too  great  to 
be  met  by  the  resources  of  the  builders  of  the  works.  For  the 
same  reason  no  pockets  should  be  left  in  the  bottom  of  reservoirs 
at  places  where  there  is  any  liability  of  the  water  becoming  shal- 
low. Such  depressions  should  be  filled  with  clean  material  in 
order  to  prevent  organisms  flourishing  in  them  during  dry  sea- 
sons. 

The  worst  odors  in  drinking  waters  are  due  to  floating  micro- 
scopic organisms,  which  are  described  in  Mr.  Gr.  C.  Whipple's 
"Microscopy  of  Drinking  Water,"  an  invaluable  book  for  water- 
works authorities  interested  in  the  cause  of  the  odors  and  tastes 
which  sometimes  occur  in  surface  waters.  Mr.  Whipple  classifies 
these  odors  and  the  organisms  producing  them  under  three  heads 
as  follows: 

Group.  Organism.  Natural  Odor. 

Aromatic.  .Diatomacese 

Asterionella Aromatic — geranium — fishy. 

Cyclotella Faintly  aromatic. 

Diatoma 

Meridion. Aromatic. 

Tabellaria " 

Protozoa 

Cryptomonas Candied  violets. 

Mallomonas Aromatic — violets — fishy. 

Grassy Cyanophyceaa 

Anabaena Grassy,  mouldy — green  corn — nastur- 
tiums. 

Rivularia Grassy,  mouldy. 

Clathrocystis Sweet,  grassy. 

iCcelosphaerium 

Aphanizomenon . . .  Grassy. 
Fishy Chlorophyceae 

Volvox Fishy. 

Eudorina    Faintly  fishy. 

Pandorina 

Dicty  osphserium ...        " 
Protozoa 

Uroglena Fishy  and  oily. 

Synura Ripe    cucumbers — bitter    and    spicy 

taste. 

Dinobryon Fishy,  like  rock  weed. 

Bursaria Irish  moss — salt  marsh — fishy. 

Peridinium Fishy,  like  clam  shells. 

Glenodinium Fishy. 

In  this  table  it  will  be  noticed  that  after  certain  organisms 
there  are  several  odors,  separated  by  dashes.  This  signifies  that 
as  the  numbers  of  the  organisms  increase  they  impart  different 
odors  to  the  water.  Asterionella,  the  most  pronounced  of  all, 
gives  the  water  a  slight  aromatic  odor  when  a  few  organisms  oc- 


WATER-WORKS    MANUAL.  8? 

cur;  as  the  number  increases  the  odor  resembles  that  of  rose 
geraniums,  and  if  the  growth  continues,  the  water  has  a  nauseat- 
ing fishy  odor  which  is  very  disagreeable.  The  trouble  with  the 
water  supply  of  Brooklyn  late  in  the  summer  of  1896  was  due  to 
this  organism.  It  did  not  occur  in  sufficient  numbers  to  cause 
any  trouble  in  the  wells  and  ponds  from  which  the  supply  is 
drawn,  but  developed  rapidly  in  some  of  the  shallow  basins  used 
as  distributing  reservoirs.  The  trouble  has  been  remedied  by 
building  a  by-pass  around  the  basins  through  which  the  water 
passes  without  access  to  the  light  during  the  season  when  the  or- 
ganisms are  liable  to  grow.  Some  of  the  organisms  give  off  still 
different  odors  when  decaying,  such  as  the  pig-pen  odor  of  de- 
composing cyanophycese.  Enough  has  been  said,  however,  to 
show  that  the  numerous  cases  of  trouble  from  odors  can  be  traced 
in  most  cases  to  a  few  species  of  organisms.  It  will  take  a  biolo- 
gist but  a  short  time  to  determine  which  species  is  responsible  in 
any  given  case.  Unfortunately,  it  is  not  such  a  simple  matter  to 
devise  a  satisfactory  remedy,  and  in  the  present  state  of  knowl- 
edge on  this  subject,  no  general  advice  of  any  value  can  be  of- 
fered. 


CHAPTER  VII.— GROUND- WATER  SUPPLIES. 

The  growing  importance  of  ground-water  supplies  in  this  coun- 
try makes  it  important  to  go  into  the  classification  of  such  sup- 
plies in  some  detail.  In  Great  Britain  and  in  Europe  the  utiliza- 
tion of  underground  water  has  been  studied  with  much  greater 
care  than  on  this  side  of  the  Atlantic,  for  the  reason  that  unpol- 
luted surface  supplies  are  relatively  rarer  there  than  here,  and  the 
American  engineer  will  find  many  instructive  examples  of  springs 
and  wells  in  use  in  foreign  water-works. 

Two  broad  classifications  of  ground  water  may  be  made  at  the 
outset.  The  first  is  the  water  which  filters  from  a  river  or  pond 
into  the  soil  forming  its  basin.  This  water  generally  retains 
many  of  the  characteristics  of  the  source  from  which  it  is  derived, 
although  it  is  often  possible  to  select  a  point  from  which  a  supply 
may  be  drawn  of  much  greater  purity  than  the  river  or  pond 
water,  owing  to  the  fact  that  the  quality  of  the  latter  has  been 
improved  during  its  passage  through  the  earth.  The  second  great 
class  of  ground  waters  includes  the  water  which  has  entered  the 
ground  from  a  variety  of  sources,  but  has  been  checked  in  its 
downward  percolation  by  more  or  less  impervious  strata.  If  the 
water  has  merely  settled  down  vertically  through  a  single  stratum, 
it  is  generally  possible  to  reach  it  with  a  shallow  well.  In  case 
the  underlying  impervious  stratum  is  inclined,  the  water  will  flow 
down  along  its  upper  surface  until,  possibly,  the  pervious  stratum 
in  which  the  water  is  confined  is  overlaid  in  turn  by  another  im.- 
pervious  stratum,  when  it  will  be  necessary  to  sink  a  deep  well  to 
secure  a  supply.  In  case  the  inclined  pervious  stratum  finally 
opens  to  the  air,  it  will  lose  its  water  by  a  spring  at  the  outcrop. 
Sometimes  all  the  strata  are  inclined  for  a  long  distance,  so  that 
the  water  in  the  porous  bed  at  the  bottom  of  the  incline  is  under 
considerable  pressure.  If  the  distance  from  the  surface  of  the 
ground  at  this  place  down  through  the  impervious  strata  to  the 
water-bearing  rock  or  earth  is  much  less  than  the  difference  in 


WATER-WORKS    MANUAL.  89 

elevation  between  the  point  where  the  water  entered  the  earth 
and  the  foot  of  the  inclined  porous  stratum,  then  a  well  sunk  at 
the  latter  point  will  be  what  is  called  an  artesian  well,  and  the 
water  will  rise  in  it  above  the  surface  of  the  ground.  This  term, 
artesian  well,  is  often  used  incorrectly  to  designate  a  deep  well. 
The  different  classes  of  well  are  shown  in  Figure  15. 

METHODS  OF  COLLECTING  GROUND  WATER. 

With  regard  to  the  methods  of  collecting  ground  water,  it  is 
evident  that  no  one  plan  is  applicable  to  all  cases,  but  the  follow- 


Porous.        Artesian 

Deep  Well. 
Shallow  Well 


FIGURE  15. -DIAGRAM  OF  WELLS. 


ing  general  statements,  largely  based  on  Mr.  Stearns'  paper  on 
the  "Selection  of  Sources  of  Water  Supply,"  are  necessary  as  an 
introduction  to  more  detailed  descriptions.  Where  the  material 
is  coarse  and  porous  within  a  short  distance  of  the  surface  and 
the  quantity  of  water  required  is  not  very  large,  a  circular  well, 
covered  to  exclude  the  light,  is  generally  the  best.  In  other  in- 
stances, where  the  material  for  a  long  distance  from  the  surface 
is  impervious,  but  is  underlaid  with  pervious  material,  it  is  im- 
practicable to  excavate  a  large  well  to  the  required  depth,  and  it 
becomes  necessary  to  sink  tubular  wells  to  the  porous  stratum 
which  may  sometimes  be  found  overlying  the  rock. 

Tubular  wells  may  be  connected  by  means  of  a  large  suction 
pipe  directly  with  the  pump,  which  is  generally  the  cheaper  form 
of  construction,  or  they  may  be  connected  with  excavated  wells 
or  filter  galleries,  into  which  the  water  from  the  tubular  wells 
will  flow. 

Filter  galleries  are  built  in  some  instances  where  it  is  desired 
to  intercept  the  ground  water  from  a  greater  area  than  will  be  in- 


90  WATER-WORKS    MANUAL. 

fluenced  by  a  single  well.  They  are,  in  fact,  elongated  wells, 
which,  however,  are  not  usually  sunk  to  as  great  a  depth.  Filter 
basins  perform  the  -same  office  in  collecting  water  as  wells  and 
filter  galleries,  but  being  uncovered,  the  water  in  them  deterior- 
ates owing  to  the  rapid  growth  of  vegetable  and  animal  organ- 
isms which  flourish  in  this  kind  of  water  when  the  light  is  not 
excluded.  This  form  of  construction  should  therefore  be  avoided. 

There  are  many  instances  in  which  the  main  supply  comes 
from  wells  and  filter  galleries,  but  is  increased  by  means  of  driven 
wells  extending  from  them  into  porous  strata  at  lower  levels. 

In  developing  springs  it  is  generally  customary  to  make  a  sort 
of  masonry  well  about  them,  care  being  taken  that  the  work  in- 
terferes as  little  as  possible  with  the  flow.  Sometimes  tunnels  are 
driven  into  slopes  from  which  springs  issue,  in  order  to  secure 
more  water  than  a  natural  hillside  spring  will  furnish. 

In  the  case  of  very  deep  or  artesian  wells,  it  is  usually  neces- 
sary to  employ  a  well-sinker's  outfit,  or  to  let  the  work  to  con- 
tractors accustomed  to  the  operations.  The  latter  plan  is  gen- 
erally the  cheaper  and  more  satisfactory. 

QUANTITY   OF   GROUND    WATER. 

The  amount  of  water  that  may  be  obtained  from  deep  and  shal- 
low wells  is  so  often  overestimated  that  it  is  necessary  to  call  at- 
tention to  the  fact  that  the  quantity  available  depends  on  the 
same  conditions  as  the  amount  of  surface  water,  the  extent  of  the 
catchment  area,  the  rainfall,  the  proportion  of  the  rainfall  enter- 
ing the  ground  and  the  capacity  of  the  basin  to  hold  ground 
water.  There  is  also  in  this  case  an  additional  condition,  which  is 
the  porosity  of  the  soil  or  its  capacity  for  storage.  It  is  mani- 
festly impossible  to  obtain  more  water  from  the  ground  than 
enters  it,  and  hence  it  is  frequently  of  advantage  to  estimate  the 
ground  water  in  the  same  manner  as  a  surface  supply.  Mr.  F.  P. 
Stearns,  who  studied  this  subject  carefully  in  connection  with  his 
examinations  of  the  water-works  of  Massachusetts,  has  given  the 
following  outline  of  the  method  of  procedure: 

"It  is  sometimes  feasible  in  the  case  of  a  proposed  ground- 
water  supply  to  determine  whether  the  source  is  worthy  of  a  care- 
ful investigation  by  means  of  the  table  (see  page  14)  for  deter- 
mining the  volume  of  surface  water  obtainable  with  different 
amounts  of  storage.  If,  for  instance,  it  is  desired  to  obtain  a  sup- 
ply of  300,000  gallons  a  day,  and  the  watershed  draining  toward 


WATER-WORKS    MANUAL.  91 

the  proposed  well  is  1  square  mile,  we  find  from  the  table  that  in 
the  case  of  a  surface  water  supply  the  storage,  when  there  are  no 
water  surfaces,  must  be  29,800,000  gallons.  If  the  supply  is  to  be 
taken  from  the  ground  it  seems  fair  to  assume  that  at  least  an 
equal  amount  of  storage  will  be  required;  and  the  question  to  be 
considered  relates  to  the  probability  of  obtaining  this  amount  of 
available  storage,  which  is  equivalent  to  the  contents  of  a  pond 
having  an  area  of  10  acres  and  a  depth  of  9  feet.  Porous  gravel 
or  sand  when  saturated  contains  in  the  neighborhood  of  35  per 
cent,  of  water,  but  of  this  a  portion  remains  after  the  ground  ia 
drained,  so  that  only  about  25  per  cent,  of  the  whole  mass  will 
run  out  when  the  water  table  is  lowered.  Therefore,  in  order  to 
obtain  300,000  gallons  daily  from  a  square  mile  during  the  driest 
period,  it  is  necessary  to  have  a  storage  equivalent  to  that  fur- 
nished by  40  acres  of  porous  gravel  in  which  the  water  table  can 
be  lowered  9  feet.  A  superficial  examination  of  the  ground 
may  show  whether  it  is  probable  that  this  amount  of  storage  can 
be  obtained  and  in  this  way  indicate  whether  it  is  desirable  to 
make  further  investigations." 

The  presence  of  water  near  the  surface  may  be  tested  by  sink- 
ing a  tube  well  and  pumping  from  it  by  hand,  if  the  quantity 
wanted  is  small,  or  by  means  of  a  small  portable  steam  plant  if 
the  works  are  to  be  of  a  fair  size.  The  water  may  be  measured 
with  sufficient  accuracy  by  letting  it  flow  over  a  small  weir  at  the 
end  of  a  plank  trough.  Small  centrifugal  pumps  are  generally 
used  on  these  tests.  It  is  desirable  to  sink  several  tubes  sepa- 
rated by  distances  depending  on  the  character  of  the  soil,  so  that 
the  fall  of  the  ground  water  due  to  pumping  from  one  well 
can  be  measured  in  the  others.  In  French  and  German  text- 
books on  water  supply,  there  are  often  elaborate  mathematical 
investigations  of  the  yield  of  tube  wells  in  various  soils,  but  while 
these  may  be  of  theoretical  interest,  they  are  of  very  little  actual 
value.  It  is  such  an  easy  and  inexpensive  matter  to  make  the 
necessary  tests  for  a  small  plant,  that  there  is  no  excuse  for  fail- 
ing to  do  so,  especially  as  the  results  of  such  an  examination  fre- 
quently indicate  that  the  best  location  for  the  wells  is  not  shown 
by  surface  indications. 

One  great  advantage  of  thorough  tests  of  this  nature  is  that 
they  show  the  nature  of  the  water-holding  basin.  This  is  a  very 
important  matter,  for  it  may  happen  that  an  apparently  abun- 


92  WATER-WORKS    MANUAL. 

dant  supply  will  suddenly  give  out,  owing  to  the  water  being 
drawn  from  a  large  basin  with  a  small  tributary  catchment  area. 
For  a  year  or  so  such  a  basin  may  furnish  an  ample  supply,  but 
after  its  water  table  has  been  drawn  down  the  catchment  area  is 
too  small  to  meet  the  draft.  It  is  believed  that  the  partial  failure 
of  the  first  well  of  the  Peoria  Water  Company  was  due  to  this 
cause;  at  first  it  furnished  an  apparently  unlimited  supply  of  ex- 
cellent water,  but  after  a  few  years  it  began  to  dry  up.  There  is 
no  apparent  chance  for  the  silting  of  the  well.  The  late  A.  F. 
ISToyes  stated  that  he  kept  a  6-inch  centrifugal  pump  running  at 
its  full  capacity  day  and  night  for  several  weeks  to  drain  a  coarse 
gravel  in  which  a  sewer  was  being  laid.  It  was  about  a  month 
before  any  appreciable  drop  in  the  level  of  the  water  was  ob- 
tained, but  when  the  pumps  finally  made  an  impression,  the  basin 
gave  out  suddenly  and  the  water  did  not  recover  its  level  for  a 
long  time. 

Where  deep  or  artesian  wells  are  necessary  it  is  evident  that  a 
careful  geological  examination  of  the  country  is  necessary.  In 
those  States  which  have  supported  geological  surveys,  valuable  in- 
formation can  often  be  obtained  from  their  officers  or  their  pub- 
lished reports,  and  the  United  States  Geological  Survey  can  some- 
times supply  desirable  data;  in  fact,  the  maps  of  the  last  body  are 
of  great  value  to  the  water-works  designer.  Deep  and  artesian 
wells  generally  draw  water  from  inclined  strata  passing  under 
many  townships,  and  an  investigation  in  the  neighborhood  will 
sometimes  enable  an  engineer  to  form  a  pretty  close  estimate  of 
the  distance  it  is  necessary  to  sink  a  well  in  order  to  reach  a  sup- 
ply of  water.  There  is  always  a  chance  of  faults  and  other  geo- 
logical accidents  in  the  neighborhood,  however,  and  hence  every- 
one looking  for  an  underground  supply  must  bear  in  mind  that 
the  search  is  not  certain  to  be  successful. 


CHAPTER  VIII.— THE  UTILIZATION  OF  SPRINGS. 

One  of  the  characteristic  general  features  of  French  and  Ger- 
man water-works,  as  compared  with  American  practice,  is  the  de- 
velopment and  utilization  of  springs  as  sources  of  supply  for 
small  communities.  In  those  countries,  as  previously  remarked, 
the  large  population  and  the  proprietary  rights  in  streams  and 
ponds  tend  to  compel  engineers  to  study  ground  water  with  much 
care,  and  it  is  worth  the  attention  of  American  engineers  to  ex- 
amine the  foreign  practice  in  this  respect.  This  chapter  is  in- 
tended to  present  a  very  brief  summary  of  the  methods  in  vogue 
abroad  to  utilize  springs,  and  is  largely  based  on  Herr  Lueger's 


FiG.18 


FlQ.19 


voluminous  work  on  the  water  supply  of  cities,  to  which  reference 
has  previously  been  made. 

In  case  an  underground  stream  feeds  several  springs,  which  is 
not  rarely  the  case,  the  development  of  one  spring  and  the  inter- 
ception of  the  water  in  the  others  by  means  of  a  tunnel  or  trench 
will  often  increase  the  yield  of  the  first  spring  at  the  expense  of 
the  others.  This  plan  is  frequently  adopted. 

If  it  has  been  determined  that  a  spring  Q,  Figure  16,  starts 
from  a  plane  of  stratification  sloping  in  the  direction  of  the  ar- 


94  WATER-WORKS    MANUAL. 

rows  in  the  cut,  it  is  evident  that  a  large  part  of  the  water  flows 
past  the  spring.  The  latter,  indeed,  owes  its  existence  to  the  re- 
cess of  the  hillside  in  the  neighborhood  of  Q.  In  case  a  tunnel 
is  driven  into  the  hillside  over  the  impermeable  stratum,  as  indi- 
cated by  the  heavy  line,  the  yield  of  water  will  be  greatly  in- 
creased, the  amount  of  the  increase  depending  on  the  area  of  the 
surface  supplying  water  to  the  portion  of  the  porous  stratum  cut 
by  the  tunnel. 

Much  the  same  conditions  exist  in  the  case  shown  in  Figure  17, 
which  is  generally  somewhat  common.  In  this  cut  Q  is  the 
spring,  A  Q  B  the  outcrop  of  a  stratum,  of  which  the  arrows  show 
the  slope.  As  a  rule  no  Avater  is  visible  along  the  lines  A  Q,  B  Q, 
which  are  usually  hidden  by  a  mass  of  loose  rock  or  by  a  meadow 
which  shows  the  presence  of  water  by  its  dampness.  The  threads 
of  water  can  be  intercepted  by  a  ditch  or  tunnel  located  as  shown, 
which  will  make  the  spring  of  useful  size. 

An  increase  in  the  delivery  of  a  spring  is,  moreover,  always  pos- 
sible in  cases  where  the  pervious  and  impervious  strata  follow  in 
regular  succession,  as  indicated  in  Figure  18.  The  hillside  tun- 
nels of  the  Oakland,  CaL,  works  are  excellent  examples;  see  "The 
Engineering  Kecord"  of  June  15,  1895.  In  this  case  a  tunnel  is 
driven  so  as  to  pierce  the  alternating  water-bearing  strata,  and 
the  result  is  especially  satisfactory  if  at  A  there  is  a  fairly  level 
valley  with  considerable  soil  from  which  water  can  be  drawn.  It 
is  self-evident  that  in  case  the  single  tunnel  does  not  furnish  the 
full  supply  desired  the  yield  can  be  increased  by  driving  branch 
tunnels  on  either  side  in  the  porous  strata,  thus  intercepting  a 
greater  portion  of  their  delivery  in  the  manner  illustrated  in 
Figure  17. 

In  alluvial,  glacial  and  similar  beds,  it  often  happens  that  thin 
sheets  or  tongues  of  barely  permeable  clay  and  marl  are  encoun- 
tered. In  case  a  very  small  spring  is  found  at  the  outcrop  of  such 
a  sheet,  while  the  area  of  the  catchment  basin  would  indicate  the 
probability  of  more  water  being  available,  it  is  advisable  to  search 
for  artesian  or  "living"  water.  Figure  19  shows  such  a  clay 
tongue  in  a  gravel  bed.  It  is  apparent  that  by  boring  at  the  site 
of  the  spring  the  water  in  the  reservoir  below  the  clay  will  be 
tapped,  and  it  is  possible  that  it  will  rise  with  considerable  force 
so  as  to  form  an  artesian  well  on  a  small  scale.  It  is  in  such 
formations  that  "living"  or  "bubbling"  springs  often  occur;  these 


WATER-WORKS    MANUAL.  95 

are  the  overflows  of  a  large  ground-water  system,  and  supplies  of 
considerable  volume  can  generally  be  obtained  by  proper  develop- 
ment. 

In  the  development  of  every  spring  care  must  be  taken  that 
the  water  is  clear  before  it  enters  the  outlet  pipe,  and  it  is  some- 
.  times  necessary  to  provide  sand-pits  and  clear-water  chambers  in 
order  to  accomplish  this.  For  the  same  reason,  the  mouth  of  the 
outlet  pipe  should  be  from  1  to  3  feet  above  the  bottom  of  the 
chamber  at  which  it  starts  and  be  protected  by  a  screen.  The 
spring  ought  to  be  covered  by  some  sort  of  housing  which  will 
keep  out  leaves,  frogs  and  similar  objects  while  allowing  free  ac- 
cess for  inspection  and  cleaning.  .  It  has  been  noticed  frequently 
that  a  spring  is  affected  injuriously  if  its  surface  is  raised  above  a 
certain  level,  and  on  that  account  an  overflow  of  sonu  form  is 
often  constructed' to  prevent  automatically  such  an  elevation. 

It  is  well  to  notice  that  there  are  two  classes  of  springs  before 
passing  to  a  brief  description  of  the  works  developing  them,  as 
the  latter  vary  considerably  according  to  the  class  which  they  im- 
prove. The  first  are  the  springs  in  level  tracts  where  the  water 
rises  from  a  lower  reservoir  or  stream,  and  the  second  are  the 
springs  on  hillsides. 

The  first  has  usually  a  small  discharge  which  can  easily  be  col- 
lected in  a  single  basin,  and  so  long  as  the  water  level  is  not  essen- 
tially changed  this  method  of  development  has  little  or  no  in- 
fluence on  the  quantity  or  quality  of  the  water.  If  the  water 
level  is  much  lowered,  the  discharge  is  frequently  increased  by  a 
considerable  amount,  although  this  is  usually  done  at  the  expense 
of  neighboring  springs  at  higher  elevations. 

The  case  is  different,  however,  in  the  development  of  springs 
which  originate  at  the  outcrop  of  pervious  strata  on  a  hillside. 
With  these  it  is  necessary  to  work  into  the  hillside  in  order  to  col- 
lect the  water,  and  the  development  frequently  results  in  a  dimin- 
ution of  the  original  volume  of  the  spring. 

SPRINGS  IN  PLAINS. 

If  a  spring  occurs  in  an  extensive  level  plain,  it  is  generally 
developed  by  constructing  a  basin  about  it.  If  the  basin  is  left 
open,  it  usually  becomes  filled  with  weeds,  frequented  by  frogs, 
and  polluted  with  leaves  and  surface  water,  rendering  it  useless 
as  a  source  from  which  to  draw  drinking  water.  Some  large  open 
basins,  such  as  the  famous  Danube  Spring  at  Donaueschingen, 


96 


WATER-WORKS    MANUAL. 


cover  such  a  large  area  and  are  so  protected  by  masonry  walls  and 
parapets  that  their  water  is  fairly  good.  As  a  rule,  however,  such 
springs  must  usually  be  provided  with  a  well  of  masonry  and  a 
roof  if  they  are  to  be  used  as  a  source  for  drinking  water,  and 
care  must  be  taken  that  there  is  no  possibility  of  polluted  surface 
water  fouling  them. 

The  bubbling  springs  in  tracts  where  no  pollution  is  possible 
have  been  utilized  in  some  districts,  particularly  in  the  Black 
Forest.  Herr  Lubberger  has  given  a  description  of  several  such 
springs,  from  which  the  following  extract  is  made: 

"In  several  places,  particularly  near  Loeffingen,  I  laid  bare  the 
surface  of  the  mouth  of  the  spring,  and  then  collected  the  springs 


FiG.21 


FiG.20 


breaking  out  at  various  points  by  means  of  a  network  of  tile 
drains.  This  network  was  covered  with  a  concrete  slab  protecting 
it  from  the  earth  above,  which  was  given  a  roof  shape  to  shed  the 
rain  water;  see  Figure  20.  A  ventilating  shaft  is  necessary,  of 
course.  In  another  case,  in  which  I  could  not  lead  away  the 
water,  I  surrounded  the  excavation  with  sheet-piling,  filled  the 
entire  area  in  which  the  springs  appeared  with  large  stones,  and 
covered  this  over  watertight." 

The  latter  design  is  recommended  highly  by  Herr  Lueger  on 
account  of  its  simplicity  and  low  cost,  and  he  suggests  the  use  of 
clay  as  a  covering.  Figure  21  is  a  sketch  of  such  a  design,  which 
has  the  advantage  of  being  readily  and  cheaply  opened  for  inspec- 


tion and  cleaning  at  any  time. 


Some  method  of  ventilation  is 


WATER-WORKS    MANUAL. 


97 


necessary,,  and  he  suggests  a  vertical  pipe  with  a  cowl,  shown  in 
the  sketch,  as  an  appropriate  plan. 

Elaborate  masonry  work  has  been  employed  at  some  of  the 
springs  utilized  by  the  Paris  water-works.  Figure  22  shows  the 
chamber  of  the  spring  of  Armentieres,  which  is  circular  in  plan 
and  about  32.8  feet  in  diameter.  The  very  flat  dome  roof  covered 
with  earth  exerts  a  considerable  pressure  on  the  wall,  which  is  re- 
inforced  by  buttresses  on  this  account.  The  chamber  is  reached 
through  a  doorway,  and  has  a  gallery  around  the  interior.  There 
is  no  overflow,  but  a  drain  has  been  provided  for  drawing  off  the 
water  when  the  chamber  is  to  be  cleaned;  the  doorway  affords 


FlG.22 


ventilation.  This  design  has  given  good  service.  In  some  cities 
the  works  erected  about  the  springs  are  of  a  monumental  charac- 
ter, with  elaborate  entrance  towers,  as  at  Lille,  for  example.  Such 
elaboration,  however,  does  not  find  favor  with  many  of  the  con- 
tinental engineers. 

HILLSIDE  SPRINGS. 

The  springs  issuing  from  the  side  of  a  hill  or  mountain  have 
to  be  treated  in  an  entirely  different  manner  from  that  followed 
when  the  water  rises  vertically  in  a  plain.  In  the  former  cas*1  the 
character  of  the  springs  must  be  studied  first.  The  separate 
threads  of  water  from  which  the  spring  is  formed  must  be  sought 
out,  the  impermeable  stratum  must  be  found,  or  in  case  this  is  far 
distant,  as  when  the  water  emerges  from  a  fissure,  the  immediate 
cause  of  the  spring  must  be  ascertained. 


08  WATER-WORKS    MANUAL. 

A  spring  located  at  the  foot  of  steep  slopes  or  cliffs  is  mani- 
festly little  exposed  to  pollution  by  surface  water,  and  the  work 
t)f  development  is  little  more  than  the  construction  of  a  suitable 
chamber  about  and  over  it.  The  case  is  different,  however,  when 
the  spring  rises  on  a  gently  sloping  hillside  and  pervious  soil  lies 
'over  the  course  of  the  ground  water.  Such  a  spring  is  polluted 
by  the  surface  water  after  a  protracted  rainfall,  and  it  is  necessary 
to  make  a  large  area  of  the  overlying  surface  impervious  or  to 
trace  the  spring  back  into  the  hillside  until  it  is  some  8  to  10  feet 
below  the  surface.  When  this  is  done,  the  various  threads  of 
water  must  generally  be  intercepted  by  a  tunnel  or  other  work, 
and  the  result  is  often  a  diminution  in  the  volume  of  water  dis- 
charged. 

When  a  spring  is  followed  back  into  a  hillisde  in  this  way,  care 
must  be  taken  that  there  is  no  chance  of  surface  water  flowing 
along  the  tunnel  toward  the  spring,  and  the  entrance  must  be 
made  large  enough  for  the  passage  of  any  materials  likely  to  be 
needed  in  repairs  or  cleaning.  Any  branch  collecting  galleries 
leading  into  the  porous  strata  should,  if  lined,  have  a  clear  cross- 
section  not  less  than  about  5J  by  2-J  feet.  This  section  allows  a 
light  wooden  working  platform  to  be  laid  on  permanent  iron  sup- 
ports when  it  is  desired  to  clean  the  channels.  In  the  galleries 
built  at  the  Vannes  springs  of  the  Paris  water-works,  the  platform 
is  a  permanent  masonry  structure  which  interferes  with  the  clean- 
ing of  the  channel  below.  It  is  also  necessary  to  make  some  pro- 
vision for  a  circulation  of  air  in  the  spring  chamber  in  case  this 
cannot  be  secured  through  the  entrance;  a  ventilating  pipe  with 
a  hood  or  cowl  running  up  from  the  highest  part  of  the  roof  is  the 
simplest  method  in  most  cases. 

Every  outlet  pipe  from  such  a  spring  should  be  provided  with 
a  strainer  at  its  mouth,  and  be  some  distance  above  the  bottom  of 
the  chamber,  so  that  the  water  entering  it  will  be  free  from  solid 
matter.  In  case  the  strainer  becomes  clogged,  or  the  gate  is 
closed  in  the  outlet  pipe,  the  water  will  back  up  in  the  chamber, 
and  some  form  of  overflow,  such  as  a  weir  or  pipe,  should  be  pro- 
vided. It  is,  of  course,  desirable  to  have  some  means  of  determin- 
ing the  flow  of  water  from  the  spring  in  case  it  is  of  considerable 
size,  and  for  this  purpose  the  chamber  or  the  galleries  leading  to 
it  may  be  arranged  so  as  to  permit  the  construction  of  temporary 
or  permanent  weirs.  Another  plan  is  to  determine  the  capacity 


WATER-WORKS    MANUAL.  99 

of  the  basin  of  the  chamber  between  two  different  elevations,  and 
then  find  how  long  it  will  take  the  spring  to  raise  the  water  sur- 
face from  the  lower  to  the  upper  level;  from  this  information  it  is 
a  simple  matter  to  calculate  the  discharge.  In  case  the  water  con- 
tains much  sand,  as  springs  flowing  from  sandstone  formations 
are  liable  to  do,  it  may  be  necessary  to  construct  a  sand-pit  like 
those  used  on  the  head  works  of  plants  drawing  supplies  from 
mountain  streams.  The  sand-pit  is  simply  a  long,  comparatively 
deep  and  wide  basin,  in  which  the  velocity  of  the  stream  is  check- 
ed sufficiently  to  cause  all  suspended  matter  to  settle  to  the 
bottom. 

The  application  of  these  principles  is  best  shown  by  studying  a 
design  embodying  them.  Figure  23  represents  a  small  spring 
chamber  designed  by  Herr  Lueger.  It  is  walled,  arched  and  cov- 


FiG.23 

ered  with  earth.  It  is  accessible  through  a  sharply  inclined  en- 
trance furnished  with  two  folding  doors  or  a  removable  cover. 
Within  the  entrance  is  a  shaft  for  descending  to  the  basin  and 
thus  reaching  the  spring.  This  shaft  is  drained  by  a  pipe  indi- 
cated by  the  dotted  lines,  which  leads  away  all  surface  water  that 
may  enter  through  the  opening  above;  this  pipe  also  serves  as  an 
outlet  for  the  overflow  U  of  the  basin.  A  drain  pipe  for  drawing 
off  the  water  in  the  basin  joins  the  same  pipe,  and  can  be  opened 
and  closed  by  a  plug  fitted  with  a  handle.  The  main  outlet  pipe 
has  a  cylindrical  screen  S  over  its  mouth.  The  opening  between 
the  shaft  and  the  main  chamber  can  be  fitted  with  doors  in  case 
it  appears  necessary  to  guard  against  frost  or  heat.  The  venti- 
lation is  amply  provided  for  by  the  entrance  shaft.  The  water 
from  the  spring  passes  through  an  opening  in  the  rear  wall,  which 


100  WATER-WORKS    MANUAL. 

is  backed  by  large  stone  and  gravel  to  keep  back  the  sand.  In 
case  the  latter  enters  the  chamber  in  an  appreciable  amount  the 
dimension  a  of  the  chamber  should  be  increased  so  as  to  give  a 
basin  of  sufficient  size  to  form  a  sand  pit.  It  is  assumed  that  the 
spring  chamber  can  be  somewhat  sunk  into  the  impermeable 
stratum.  If  this  condition  cannot  be  filled  the  spring  must  be 
collected  in  a  pipe  or  other  channel,  and  the  chamber  must  be 
covered  somewhat  deeper  or  sufficient  protection  against  infiltra- 
tion provided  otherwise. 

The  criticism  may  be  made  against  this  chapter  that  it  advo- 
cates antiquated  and  costly  principles  and  methods,  but  the  writer 
has  already  stated  as  clearly  as  he  can  that  these  underground 
sources  of  supply  are  at  best  something  of  a  gamble,  and  are  not 
to  be  employed  when  good  surface  supplies  are  as  readily  secured. 
On  the  other  hand,  American  engineers  have  not  practised  the 
development  of  ground  water  sources  to  the  same  extent  as  their 
colleagues  across  the  Atlantic,  and  in  view  of  the  successful  new 
works,  especially  small  works,  which  are  being  constructed  abroad 
for  the  utilization  of  such  sources  by  the  means  outlined  in  this 
chapter,  or  by  others,  to  be  described  later  in  connection  with 
wells,  it  is  believed  that  an  important  feature  of  water-works  de- 
sign would  remain  unmentioned  without  these  notes. 


CHAPTER  IX.— OPEK  WELLS. 

The  two  classes  of  open  wells  which  have  been  used  for  water- 
works purposes  are  those  of  large  diameter  and  comparatively 
shallow  depth,  which  include  most  American  wells,  and  those  of 
small  diameter  but  considerable  depth  usually  extended  down- 
ward by  a  bore  hole  or  driven  well.  This  latter  class  has  been 
developed  mainly  to  obtain  water  from  the  chalk  formations  of 
England,  although  it  is  coming  into  favor  in  Germany. 

Large  shallow  wells  sunk  near  rivers  or  lakes  are  liable  to  fur- 
nish a  supply  of  genuine  groundwater  more  or  less  mixed  with 
less  desirable  water  from  such  sources.  When  such  a  well  is  in 
regular  service,  the  profile  of  the  ground-water  surface,  as  shown 
on  a  vertical  cross-section  through  the  well,  approaches  that  of  a 
parabola.  The  curve  is  called  in  theoretical  investigations  a  de- 
pression curve,  and  its  form  varies,  of  course,  with  the  draft  from 
the  well,  the  nature  of  the  walls  of  the  well  and  surrounding 
earth,  the  available  quantity  of  ground-water,  and  the  slope  of 
the  water  table,  or  top  of  the  ground-water,  before  the  construc- 
tion of  the  well.  While  the  theoretical  investigations  of  these 
curves  and  surfaces  have  no  immediate  practical  application,  it  is 
of  value  to  determine  their  form  by  a  combination  of  theoretical 
and  experimental  methods,  if  it  can  be  done  without  too  great  an 
expenditure  of  time  and  money,  as  the  knowledge  thus  gained  is 
useful  in  estimating  the  effect  on  the  well  of  neighboring  bodies 
of  water.  It  has  been  determined  experimentally  that  the  depres- 
sion-curve of  even  small  wells  may  begin  anywhere  from  200  to 
400  feet  from  the  well.  Hence  the  natural  fall  of  the  ground- 
water  of  a  large  area  will  be  changed  by  such  a  well,  and  there 
will  be  a  tendency  to  draw  water  toward  it  from  any  neighboring 
stream  or  pond  within  this  area,  although  under  normal  condi- 
tions there  would  be  no  such  tendency. 

Wells  of  this  sort  may  be  divided  into  two  classes,  according  as 
the  walls  are  tight  or  pervious,  the  latter  being  comparatively  rare 


102  WATER-WORKS    MANUAL. 

in  this  country.  The  wells  with  tight  walls  and  no  bottom 
are  used  where  the  water  is  obtained  from  a  stratum  through 
which  the  water  moves  freely.  The  proper  diameter  to  give 
such  a  well  to  enable  it  to  yield  a  maximum  supply  depends  upon 
a  number  of  factors.  Where  the  water-bearing  stratum  is  fine 
sand,  a  marked  increase  in  the  yield  can  usually  be  secured  by  en- 
larging the  diameter  of  the  well,  but  this  is  not  the  case  with 
coarse  gravel  and  the  like.  The  main  advantage  of  a  large  well, 
however,  is  that  it  acts  as  a  reservoir,  preventing  great  fluctua- 
tions in  the  water  level  and  consequently  in  the  depression  curve. 
Regularity  and  uniformity  in  the  draft  from  such  wells  is  very 
desirable,  and  the  reserve  supply  of  water  in  a  large  well  is  useful 
for  attaining  this  condition.  Large  wells  possess  the  further  ad- 
vantage that  the  rate  of  the  now  of  water  into  them  is  lees  than 
with  small  wells,  and  there  is  therefore  less  liability  of  particles 
of  sand  and  earth  being  displaced  by  the  passage  of  the  water. 
This  consideration  is  of  less  weight  where  gravel  furnishes  the 
water  than  where  sand  occurs;  it  is  possible  that  the  sanding  of 
many  wells  might  have  been  prevented  had  attention  been  paid  to 
this  feature.  As  a  matter  of  record,  the  .following  figures  are 
quoted  here  from  Herr  Thiem's  description  of  the  water-works  of 
Nuremburg,  as  to  the  vertical  velocity  of  water  in  inches  per  sec- 
ond which  will  keep  floating  particles  of  sand  of  the  sizes  (in  frac- 
tions of  an  inch)  mentioned: 

Size 0010    0.010-0.020    0.020-0.039    0.039-0079    0.0790.118 

Velocity 1.14      1.38-2.72      2.95-3.78      4.33-0.69      7.08-32.28 

The  slight  velocity  necessary  to  take  the  smaller  sizes  of  sand 
into  suspension  indicates  that  where  a  well  must  draw  its  supply 
from  a  stratum  of  such  sand,  the  bottom  should  be  covered  with 
coarse  sand  and  gravel  in  graded  sizes,  which  will  act  as  a  sort  of 
filter  to  hold  back  the  fine  particles  when  the  velocity  of  the 
ground-water  stream  is  great  enough  to  displace  them.  This 
principle  was  used  many  years  ago  by  the  late  William  Gill  in 
constructing  wells  with  pervious  walls,  and  various  modifications 
of  his  plans  have  since  been  adopted.  In  the  more  recent  wells 
of  this  class,  the  walls,  which  have  numerous  openings  in  them, 
are  surrounded  by  layers  of  sand  and  gravel  of  graded  sizes,  the 
coarsest  being  next  the  walls  and  on  the  bottom  of  the  well. 

The  construction  of  small  wells  is  comparatively  a  simple  mat- 
ter, especially  when  they  are  to  be  lined  with  brickwork.  Form- 


WATER-WORKS    MANUAL.  103 

erly  it  was  customary  to  sink  them  like  open  bridge  caissons, 
using  a  timber  curb  on  which  the  brickwork  was  built  up  as  the 
well  was  excavated.  The  friction  of  the  earth  against  the  ma- 
sonry frequently  prevented  the  latter  sinking  as  intended,  and 
another  well  would  then  be  started  inside  the  first  and  carried 
down  in  a  similar  manner  until  the  weight  of  its  masonry  like- 
wise proved  insufficient.  This  method  of  sinking  may  still  be 
used  to  some  extent,  but  it  has  been  abandoned  generally  in  favor 
of  the  more  rapid  method  of  underpinning.  This  consists  of 
sinking  a  shaft  as  deep  as  seems  safe,  and  then  lining  it  with  ma- 
sonry started  on  a  wood  or  iron  curb.  The  shaft  is  then  sunk  a 
few  feet  farther,  and  the  masonry  built  up  from  the  bottom  to 
join  that  already  laid.  Various  plans  are  adopted  to  prevent  the 
masonry  from  falling  when  the  earth  below  it  is  removed,  which 
is  not  liable  to  occur  in  most  places  if  the  upper  courses  are 
backed  with  well-rammed  earth,  on  account  of  the  great  frictional 
resistence  of  such  a  shaft.  Sometimes  three  courses  of  brickwork 
are  laid  in  cement  every  5  feet  or  so  to  form  stiff  rings,  and  some- 
times iron  curbs  are  laid  in  the  lining  and  hung  by  ties  to  beams 
higher  up  in  the  well.  Another  plan  is  to  use  raking  props  to 
support  the  existing  lining.  In  this  last  case,  after  one  section  of 
the  lining  has  been  completed,  a  small  shaft  is  sunk  to  a  depth  of 
a  few  feet,  and  a  footing  block  bedded  firmly  on  the  bottom. 
Then  slanting  trenches  are  cut  in  the  earth  so  that  struts  can  be 
placed  between  the  curb  and  the  block.  As  soon  as  these  timbers 
are  wedged  into  place  the  masonry  is  generally  held  well  enough 
to  enable  the  earth  to  be  excavated  for  the  next  course,  which  is 
laid  on  a  curb  like  the  first,  this  method  of  working  being  con- 
tinued until  the  desired  depth  is  attained.  It  is  customary  to  lay 
the  upper  part  of  the  masonry  in  good  cement  mortar  so  as  to  pre- 
vent surface  water  from  filtering  into  the  well,  but  otherwise  only 
occasional  courses  are  laid  in  cement,  for  the  sake  of  stiffness,  as 
before  mentioned.  The  methods  employed  in  sinking  large  wells 
are  many,  as  the  following  paragraphs  will  show: 

The  brick  well  of  the  Rhinelander,  Wis.,  water-works  is  30  feet 
in  diameter,  and  was  sunk  through  loam,  clay  and  gravel.  The 
curb  was  formed  of  eight  thicknesses  of  oak  plank.  The  bottom 
two  courses  were  about  6  inches  wide,  the  next  two  8  inches,  the 
next  two  12  inches  and  the  top  two  were  16  inches.  The  outside  of 
the  curb  was  formed  by  a  ring  of  vertical  oak  plank  measuring 


104  WATER-WORKS    MANUAL. 

2  x  8  x  63  inches.  They  were  spiked  to  the  horizontal  courses  so 
as  to  form  a  sort  of  cutting  edge  about  8  inches  below  the  latter 
and  also  a  backing  to  the  lower  courses  of  the  brickwork.  This 
was  started  on  top  of  the  curb  as  a  16-inch  wall  3  feet  high,  on 
top  of  which  a  sill  of  two  courses  of  timber  was  placed.  This  sill 
was  connected  to  the  lower  one  by  anchor  bolts  running  through 
the  masonry,  and  the  outside  ring  of  vertical  plank  was  spiked  to 
it  as  well  as  to  the  curb.  The  main  wall  of  the  well  was  built  on 
the  sill,  and  its  weight  served  to  sink  the  whole  mass  gradually  as 
the  earth  below  the  cutting  edge  was  removed  by  means  of  pick 
and  shovel. 

The  well  at  Webster,  Mass.,  has  a  clear  diameter  of  25  feet  at 
the  bottom  and  26  feet  at  the  top  and  is  30  feet  deep.  It  was 
sunk  in  sand  and  gravel  previously  tested  by  means  of  ten  2J-inch 
tube  wells,  and  is  located  about  300  feet  from  a  large  lake.  Mr. 
Frank  L.  Fuller,  M.  Am.  Soc.  C.  E.,  engineer  of  the  works,  re- 
ports that  the  excavation  was  made  by  driving  2-inch  plank  sheet- 
ing outside  of  ribs  made  of  three  or  four  thicknesses  of  3 -inch 
spruce  plank  sawed  to  the  proper  radius  and  spiked  together. 
The  sheeting  was  in  two  courses,  as  the  well  was  too  deep  for  one. 
The  water  encountered  during  the  excavation  was  removed  by 
two  6-inch  centrifugal  pumps,  the  yield  being  about  1,000,000 
gallons  in  24  hours  at  a  depth  of  30  feet.  After  the  excavation 
was  completed,  a  5-foot  dry  rubble  wall  was  started,  the  thickness 
being  reduced  at  a  height  of  3  feet  to  about  3  feet  8  inches  by  an 
inside  offset,  which  was  used  as  a  support  for  a  12-inch  brick  lin- 
ing laid  in  cement.  The  rubble  backing  was  gradually  reduced 
in  thickness  to  about  2  feet,  the  last  4  feet  being  laid  in  cement, 
and  protected  by  heavy  coping  stones  which  bind  the  stone  and 
brickwork  together  and  make  a  foundation  for  the  wooden  roof 
of  the  well.  The  cost  of  this  well  was  $13,190. 

In  sinking  wells  in  sand  containing  a  large  amount  of  water,  it 
may  prove  advisable  to  make  no  attempt  to  keep  the  water  out  of 
the  well.  If  strong  pumping  is  necessary  to  keep  the  bottom  free 
enough  for  the  men  to  work,  the  material  in  the  neighborhood  of 
the  well  may  be  affected  injuriously.  If  it  is  believed  this  will  be 
the  case,  the  core  of  the  well  must  be  removed  by  some  method 
of  dredging.  One  of  the  simplest  of  these  methods  is  the  use  of 
the  sand  bucket,  which  was  first  employed  in  sinking  a  large  well 
in  Brooklyn  many  years  ago  and  has  since  been  tried  successfully 


WATER-WORKS    MANUAL.  105 

on  a  number  of  undertakings.  The  sand  bucket  is  believed  to 
"by  the  invention  of  Messrs.  John  Bogart  and  C.  C.  Martin. 

It  is  a  sheet  steel  cylinder  about  3  feet  long  and  18  inches  in 
diameter,  open  at  the  bottom  and  closed  at  the  top,  to  which  a 
long  handle  of  3-inch  pipe  is  attached.  The  top  also  has  an  air 
valve  which  can  be  closed  by  means  of  a  line.  The  bucket  is 
forced  into  the  sand  until  it  is  completely  filled  and  all  air  driven 
out  through  the  valve.  The  latter  is  then  closed  by  means  of  the 
line  and  the  bucket  raised  to  the  surface,  its  contents  being  held 
in  place  by  the  pressure  of  the  atmosphere.  The  apparatus  works 
well  in  some  soils,  such  as  sand,  but  is  not  satisfactory  in  others. 

The  so-called  Indian  shovel  is  another  apparatus  for  removing 
material  by  hand  from  below  water.  It  consists  of  a  long  handle, 
to  the  lower  end  of  which  is  hinged  a  spoon-shaped  blade.  A 
chain  is  attached  to  a  link  running  out  from  the  sides  of  the  blade 
and  a  second  chain  is  attached  to  a  lug  riveted  to  the  bottom  of 
the  blade  at  its  back.  This  second  chain  is  kept  taut  while  the 
blade  is  forced  into  the  sand  or  gravel  by  the  handle.  When  this 
part  of  the  operation  is  finished,  the  chain  is  loosened  and  the 
front  one  tightened,  pulling  the  blade  into  a  horizontal  position 
so  that  it  forms  a  small  skip  or  bucket,  which  is  lifted  to  the  sur- 
face and  emptied. 

The  sand-jet  used  in  sinking  bridge  piers  might  also  be  em- 
ployed under  certain  conditions,  although  it  would  generally  be 
an  expensive  apparatus.  Other  apparatus  will  be  found  described 
in  the  catalogues  of  dealers  in  well  fittings.  Occasionally  large 
wells  have  been  sunk  by  the  pneumatic  process,  in  the  same  man- 
ner as  caissons  for  bridges  or  high  buildings.  The  well  of  the 
Basel,  Switzerland,  water-works  was  constructed  in  this  manner. 
The  Poetsch  freezing  process  was  used  at  a  Michigan  plant.  Any 
description  of  these  various  methods  would  be  out  of  place  here, 
however,  and  the  reader  is  referred  to  the  volumes  of  "The  Engi- 
neering Record"  for  further  information. 

The  construction  of  deep,  open -wells,  consisting  of  a  long  ma- 
sonry shaft  usually  terminating  in  a  bore-hole,  is  a  practice  that 
has  found  little  favor  in  this  country,  where  it  is  considered 
cheaper  to  construct  the  bore-hole  from  the  surface  and  dispense 
with  the  enlarged  upper  shaft.  The  latter  has  the  advantage  of 
acting  to  a  certain  extent  as  a  reservoir  and  in  some  cases  enables 
the  pumps  to  be  arranged  more  advantageously  than  in  a  plain 


106  WATER-WORKS    MA.\U^L. 

bored  well.  The  general  foreign  practice  in  regard  to  these  wells 
is  given  in  the  following  paragraphs.  Further  information  on 
the  subject  will  be  found  in  the  "Proceedings"  of  the  Institution 
of  Civil  Engineers,  Volume  XC.,  from  which  Figures  24  and  25 
have  been  taken. 

The  well  at  Workingham  is  6  feet  in  diameter  for  a  depth  of 
200  feet,  and  is  lined  with  9  inches  of  brickwork  in  cement  mor- 
tar. For  the  next  60  feet,  the  shaft  is  reduced  to  4  feet  in  diam- 
eter and  is  lined  with  4^-inch  brickwork  in  neat  cement.  For 
the  next  95  feet  an  18-inch  boring  was  made  and  lined  with  cast- 
iron  pipes  16  inches  in  diameter.  The  last  53  feet  of  the  well 
was  an  unlined  16-inch  boring.  The  4-foot  shaft  was  carried  5 
feet  up  the  6-foot  shaft  and  a  cement  joint  made  between  the  two 
to  prevent  the  entrance  of  water,  and  a  similar  joint  was  made  be- 
tween the  cast-iron  lining  and  the  4-foot  shaft.  The  strata  pen- 
etrated were  quite  varied,  including  259  feet  of  London  clay,  84 
feet  of  sand  and  clay  of  different  characters,  2  feet  of  sandstone 
and  63  feet  of  chalk  at  the  bottom.  Twelve  months  were  re- 
quired to  sink  this  well. 

Mr.  William  Matthews,  M.  Inst.  C.  E.,  sank  a  pair  of 
wells  for  the  Southampton  Water-Works  in  a  manner  that  may 
prove  useful  in  working  hardpan  and  material  of  similar  nature 
under  water.  Owing  to  the  ease  with  which  borings  are  made  in 
chalk,  he  decided  to  sink,  instead  of  one  large  well,  two  6  feet  in 
diameter  and  11|  feet  apart  to  a  depth  of  100  feet  from  the  sur- 
face. The  upper  part  of  each  was  enlarged  into  a  pump  chamber, 
resting  on  a  heavy  concrete  floor.  These  floors  were  pierced  by 
two  heavy  cast-iron  cylinders,  6  feet  in  diameter  and  6  feet  long, 
which  formed  the  entrances  to  the  wells  and  acted  as  guides  to 
the  boring  tools. 

The  boring  was  done  by  three  chisels  of  wrought  iron  with  steel 
shoes,  shown  in  Figure  24.  The  center  chisel,  with  a  plain  blade, 
was  longer  than  the  outer  ones,  each  of  which  had  a  tongue 
forged  into  its  outer  edge  to  act  as  a  guide  while  the  apparatus 
was  being  raised  and  lowered,  thus  preventing  the  tool  from  cut- 
ting into' the  sides  of  the  bore  hole.  The  boring  rods  were  3 
inches  square  and  were  furnished  in  10-foot  lengths,  which  were 
coupled  together  by  screw  joints.  The  rods  and  tool  were  dropped 
on  the  chalk  and  then  raised  a  few  feet  by  means  of  a  steam  winch 
and  cable,  this  process  being  continued  until  enough  chalk  had 


WATER-WORKS    MANUAL. 


107 


been  broken  up  to  require  removal.  The  tool  was  slowly  rotated 
by  hand  during  the  work  so  as  to  distribute  the  blows  over  the 
surface. 

The  broken  material  was  removed  by  a  miser  or  large  auger 
shown  in  Figure  25.  It  was  constructed  of  f-inch  boiler  plate 
strengthened  with  substantial  angle  irons  and  plates.  "Each 
half  of  the  lower  portion  was  made  tapering  with  a  helical  twist, 
and  where  the  upper  edge  of  one  plate  was  brought  nearly  over 
the  lower  edge  of  the  other  plate,  on  either  side,  a  hinged  flap  was 
inserted  to  retain  the  debris  entering  the  tool."  The  edge  of  each 
plate  under  the  flaps  was  furnished  with  steel-toothed  cutters. 
"Internally  the  miser  was  divided  into  two  compartments,  so  that 
in  the  event  of  one  flap-valve  failing  to  act,  the  whole  efficiency 


Screw. 


Screw. 


FIGURE  24.-  CHISEL. 


FIGURE  25.— MISER. 


of  the  tool  was  not  destroyed;  moreover,  the  motion  of  the  debris 
entering  by  one  passage  did  not  tend  to  choke  the  action  of  the 
other."  A  wrought-iron  spindle  projected  from  the  bottom  of 
the  tool  to  guide  it,  and  a  strongly  braced  rod  at  the  top  enabled 
other  rods  to  be  screwed  to  the  apparatus  to  form  a  shaft  for 
turning  it  around,  which  was  done  by  men  with  levers:  The 
miser  generally  came  up  two-thirds  full.  When  all  the  apparatus 
was  in  good  order  the  average  depth  sunk  per  day  was  about  5 
feet. 

The  well  at  Petersfield,  England,  was  started  as  a  shaft  8  feet 
4  inches  square.  Down  to  50  feet  from  the  surface,  according  to 
Mr.  Robinson,  M.  Inst.  C.  E.,  the  engineer  of  the  undertaking, 
the  strata  were  quite  dry;  at  51  feet  small  quantities  of  water  ap- 


108  WATER-WORKS    MANUAL. 

peared,  and  at  56  and  66  feet  respectively  two  fissures  were  met 
which  brought  in  considerable  quantities  of  water,  but  not  enough 
to  supply  the  town.  An  adit  or  tunnel  was  driven  on  the  course 
of  the  upper  fissure  for  a  distance  of  53  feet,  but  this  did  not  in- 
crease the  yield  as  much  as  was  anticipated.  The  lower  part  of 
the  shaft,  which  was  in  sand,  was  enlarged  to  form  a  storage 
chamber  16  feet  in  internal  diameter  and  lined  with  brickwork, 
the  floor  being  67  feet  below  the  surface.  A  bore  hole  was  then 
put  down  to  a  depth  of  96  feet  from  the  surface,  and  at  this  depth 
a  large  volume  of  water  was  obtained  from  a  sand  stratum.  The 
water  rose  in  the  chamber  4  feet  higher  than  before,  and  the  total 
supply  was  increased  to  about  7,200  gallons  an  hour. 

The  construction  of  adits  running  out  from  wells,  as  men- 
tioned in  the  last  paragraph,  is  a  method  of  increasing  the  yield 
of  large  wells  which  deserves  attention.  It  is,  of  course,  necessary 
to  drive  them  at  right  angles  to  the  direction  in  which  the  ground 
water  is  flowing.  Although  the  method  has  never  been  tried,  so 
far  as  the  author  is  aware,  he  is  of  the  opinion  that  horizontal 
tubular  wells  with  perforated  sides  might  be  driven  advantage- 
ously by  water  jetting  or  some  similar  process  from  the  sides  of 
shallow  wells  of  large  diameter  where  the  increased  draft  threat- 
ened to  silt  up  the  bottom. 


CHAPTER  X.— DRIVEN  WELLS. 

A  driven  well  is  "one  formed  by  driving  or  forcing  a  wrought- 
iron  or  galvanized-iron  tube  down  into  the  stratum  from  which 
the  water  is  to  be  taken.  These  pipes  are  generally  from  1$  to  8 
inches  in  diameter,  and  may  or  may  not  be  furnished  at  the  lower 
end  with  a  wrought-iron  or  steel  point.  Above  this  point  the 
pipes  are  perforated  for  some  distances  with  holes  to  admit  the 
water." 

Wells  of  this  type  from  60  to  100  feet  deep  were  driven  in  1849 
and  1850  by  E.  W.  Purdy,  a  Milwaukee  well-maker,,  and  in  1859 
Calvin  Horton  drove  wells  of  the  same  sort  in  East  Somerville, 
Mass.,  and  neighboring  towns.  In  1867  or  1868  he  began  to  con- 
nect a  system  of  wells  to  a  single  suction  main  leading  to  a  steam 
pump.  When  the  British- Abyssinian  campaign  was  planned  in 
1867,  the  question  of  water  for  the  troops  was  a  difficult  one  to 
solve.  Finally  Mr.  J.  L.  Norton  modified  the  American  driven- 
well  practice  for  military  purposes,  and  his  apparatus  was  used  so 
successfully  during  that  campaign  that  driven  wells  using  small 
tubes  are  frequently  called  Abyssinian  wells  in  Great  Britain  and 
on  the  Continent. 

No  better  general  description  of  driven-well  work  has  come  to 
the  author's  notice  than  one  prepared  by  the  late  Albert  F.  Noyes, 
M.  Am.  Soc.  C.  E.,  who  had  much  experience  with  these  wells. 
The  best  results  "are  usually  obtained  by  driving  an  open-end 
pipe  having  attached  to  its  lower  end  a  steel  shoe  similar  to  a  com- 
mon pipe  coupling.  This  is  first  forced  into  the  ground  and  a 
small  hollow  rod  or  pipe,  to  which  a  steel  point  is  welded,  has 
small  holes  drilled  into  it  so  that  a  jet  of  water  forced  into  the  rod 
will  discharge  into  the  holes  and  play  on  the  point  of  the  drill. 
This  loosens  the  material  about  the  point  of  the  tube,  and  a  large 
part  is  forced,  by  overflow,  out  from  the  pipe.  The  wash  pipe  is 
then  removed,  the  tube  driven  until  checked  by  the  resistance  of 
the  earth,  when  the  process  of  cleaning  out  is  renewed  until  the 
level  from  which  it  is  desired  to  take  the  water  is  reached. 


110  WATER-WORKS    MANUAL. 

"When  a  number  of  water-bearing  strata  of  coarse  material  are 
encountered,  additional  pieces  of  perforated  pipe  may  be  ad- 
vantageously inserted,  thus  materially  increasing  the  yield  and 
diminishing  the  velocity  of  the  water  flowing  into  the  pipe  at  any 
one  point,  thus  preventing  a  tendency  toward  an  inflowing  of 
the  finer  material. 

"When  it  is  desired  to  determine  the  character  of  the  strata 
through  which  the  pipe  is  being  driven,  a  sand-pump  may  be 
used  with  better  results  than  a  driving-rod.  This  is  usually  a 
metal  cylinder  of  a  little  less  diameter  than  the  inside  of  the  well 
tube,  having  a  clap  valve  at  one  end  and  a  handle  at  the  other 
which  acts  as  a  guide  to  a  rod  to  which  is  attached  a  washer 
closely  fitting  the  inside  of  the  cylinder.  The  rod  is  worked  up 
and  down,  thus  filling  the  cylinder  or  pump  with  the  material 
which  is  withdrawn.  The  process  is  continued  until  the  well  is 
cleaned  out;  after  this  the  driving  continues. 

"The  driving  of  small  tubes  is  usually  effected  by  sledges 
striking  on  an  iron-bound  wooden  block,  or  by  a  small,  portable 
pile-driver,  or  by  a  weight  running  over  a  portion  of  the  tube  and 
striking  against  an  iron  clamp.  This  weight  may  be  raised  by  a 
rope  passing  over  a  sheave  or  sheaves  attached  to  a  tripod,  or 
clamped  to  the  upper  portion  of  the  tube.  The  larger  tubes  are 
driven  by  pile  drivers-  with  large,  heavy  wooden  hammers  at- 
tached to  a  rope  which  passes  over  a  sheave  at  the  top  of  a  high 
derrick,  and  is  operated  with  steam  power.  In  driving,  great 
care  must  be  taken  to  keep  the  joints  of  the  pipe  well  screwed  up, 
for  the  jar  from  driving  has  a  constant  tendency  to  unscrew  the 
sections  of  the  pipe/' 

The  principle  on  which  driven  wells  operate  has  been  explained 
very  clearly  by  Mr.  Wynkoop  Kiersted  as  follows:  "It  is  a  well- 
known  fact  that  whenever  water  is  continuously  drawn  from  a 
well  or  system  of  wells,  a  hydraulic  slope  of  the  ground-water  is 
established,  falling  toward  the  well  or  center  of  draught,  the  pro- 
file of  which  in  any  vertical  section  is  an  irregularly  curved  sur- 
face. The  head  which  induces  and  maintains  the  flow  into  the 
well,  regardless  of  that  causing  the  natural  flow  through  the 
ground,  is  the  difference  of  level  between  the  natural  surface  of 
the  ground-water  and  that  in  the  well.  This  difference  of  level  in 
a  system  of  driven  or  bored  wells,  whether  of  the  single  or  double 
tube  kind,  depends  upon  the  vacuum  produced  by  the  pump  in  the 


WATER-WORKS    MANUAL.  Ill 

suction  pipes,  and  it  naturally  follows  that  the  nearer  the  pumps 
and  suction  pipes  are  placed  to  the  natural  level  of  the  ground- 
water,  the  less  the  frictional  resistance  in  the  suction  pipes,  the 
greater,  for  any  given  vacuum,  will  be  the  static  head  causing  the 
flow  of  water  into  the  wells.  Now,  the  resistance  of  flow  through 
the  voids  of  the  water-bearing  sands  is  too  great  to  allow  any  of 
the  available  head  to  be  consumed  in  unnecessary  resistances  in 
the  suction  pipes  and  in  the  pump  lift  above  the  natural  surface 
of  the  ground- water;  therefore,  in  my  opinion,  it  becomes  essen- 
tial to  locate  the  pumps  and  suction  pipes  very  near  or  even  below 
the  natural  level  of  the  ground-water  at  the  time  of  construction, 
and  to  proportion  the  size  or  sizes  of  the  suction  pipes  so  that 
there  will  result  but  little  friction  loss." 

Theoretically  the  diameter  of  a  driven  well  with  perforated 
sides  does  not  have  an  appreciable  influence  on  the  yield,  but  for 
practical  reasons  it  is  necessary  to  have  at  least  a  certain  extent 
of  perforated  surface.  If  this  amount  of  surface  is  not  provided, 
the  velocity  of  the  water  entering  the  well  will  exceed  the  limits 
mentioned  in  connection  with  open  wells  as  sufficient  to  take  sand 
of  various  sizes  into  suspension.  In  case  the  thickness  of  the 
water-bearing  stratum  is  known,  this  principle  enables  an  esti- 
mate to  be  made  of  the  proper  diameter  of  a  well  to  yield  a  defi- 
nite amount  of  water.  Another  factor  which  some  foreign  engi- 
neers employ  in  estimating  the  maximum  amount  a  given  well 
should  yield  is  the  greatest  permissible  depression  of  the  surface 
of  the  water,  which  they  fix  at  8  to  9  feet.  Another  very  weighty 
influence  in  selecting  the  diameter  of  the  pipe  is  the  greater  or 
less  difficulty  of  sinking  the  various  sizes  with  the  appliances  at 
hand.  It  is  not  advisable  to  choose  small  tubes  for  wells  in 
gravel  and  coarse  sand,  but  in  case  fine  sand  is  penetrated  a  large 
number  of  small  tubes  will  give  the  best  results  for  a  given  outlay. 

SINKING  WELLS. 

In  sinking  wells  in  fine  sand,  it  is  often  the  custom  to  cover  the 
screen  with  finely  woven  wire  netting  as  an  additional  precaution 
against  the  entrance  of  grit.  Sometimes  netting  is  advantageous, 
and  sometimes  it  clogs  up  so  quickly  as  to  require  cleaning  in  a 
short  time.  This  work  can  be  done  in  several  ways,  by  blowing 
high-pressure  steam  down  the  tube,  by  forcing  water  down  it  by 
means  of  a  pump,  and  by  pulling  up  the  tube  and  cleaning  the 
network  by  means  of  brushes,  jets  of  water  or  other  appliances. 


112  WATER-WORKS    MANUAL. 

In  driving  wells  in  very  fine  sand,  it  is  sometimes  advisable  to 
take  special  precautions  against  the  entrance  of  the  sand  into  the 
pipes.  One  ingenious  plan,  capable  of  various  modifications,  was 
described  in  a  paper  read  before  the  Society  of  Engineers  by  Mr. 
Robert  Sutcliff  on  the  use  of  tube  wells  for  large  water  supplies. 
A  tube  well  was  driven  at  Chislehurst  into  an  extremely  fine  sand, 
and  it  was  found  impossible  with  the  finest  strainer  to  obtain  any 
supply  of  clear  water.  The  tubes  were  withdrawn,  the  point 
screwed  off,  and  the  open  pipe  driven  into  the  same  hole.  The 
pump  was  then  attached  again,  and  four  or  five  barrow  loads  of 
sand  pumped  up.  Before  doing  this,  however,  six  barrow  loads 
of  good,  clean,  sharp  gravel  were  brought  to  the  spot.  The  pump 
was  removed,  and  down  the  tube,  which  was  1J  inches  inside 
diameter,  as  much  gravel  was  rammed  as  wras  needed.  The  open 
tube  wras  then  withdrawn,  and  a  pointed  and  perforated  tube 
driven  into  the  gravel  bed  thus  formed.  A  sand  tube  was  then 
dropped  into  the  well  to  keep  back  the  grit,  and  upon  again  at- 
taching the  pump  the  water  came  freely  and  cleared  rapidly. 

The  so-called  sand  tube  of  English  engineers  is  essentially  two 
concentric  perforated  tubes.  About  the  perforated  portion  of 
the  inner  tube  enough  horsehair  cloth  has  been  wrapped  to  fill 
completely  the  space  between  it  and  the  outer  tube. 

At  Orpington  what  is  knowrn  as  a  blowing  sand  was  dealt  with 
somewhat  similarly.  Owing  to  the  nature  of  the  sand  a  cavity 
could  not  be  made  as  in  the  previous  case.  A  hole  6  or  7  inches 
in  diameter  Avas  therefore  bored  and  piped  down  with  large  tubes 
until  several  feet  of  the  quicksand  had  been  passed.  This  quick- 
sand was  removed  from  the  pipes  with  an  ordinary  boring  shell 
and  gravel  was  rammed  down,  the  large  tubes  being  gradually 
withdrawn  as  the  work  progressed.  A  small  IJ-inch  tube  was 
then  driven  into  this  vertical  gravel  bed,  and  a  well  yielding  240 
gallons  an  hour  thus  obtained. 

The  natural  discharge  of  small  driven  wells  without  pumping 
may  be  measured  while  they  are  in  use  by  means  of  a  modification 
of  Pitot's  tube  devised  by  Mr.  A.  0.  Doane,  of  Newton,  Mass. 
"This  consists  of  two  lengths  of  -J-inch  brass  tubing  about  12  feet 
long  connected  at  the  top  by  means  of  a  inverted  U-shaped  glass 
tube,  with  an  air  cock  at  the  top,  and  the  whole  fastened  to  a 
board  for  convenient  handling.  (Figure  26).  The  board  is  cut 
off  just  above  the  ends  of  the  brass  tubes.  One  tube  is  open  at 


WATER-WORKS    MANUAL. 


113 


the  lower  end,  and  the  other  is  closed  and  has  a  fine  opening  on 
the  side.  To  use  these  tubes  they  are  inserted  in  the  well  so  as  to 
extend  down  below  the  T  branch  connecting  into  the  24-inch 
main;  an  air  pump  is  connected  with  the  air  cock  and  the  water 
raised  until  it  appears  in  both  branches  of  the  U.  On  closing 
the  cock,  the  water  drops  slightly  in  one  of  the  branches  and  the 
difference  in  level  in  the  two  branches  is  the  head  under  which 
the  water  is  flowing,  or  the  value  of  li  in  the  formula  v  =  Vtgh. 
These  tubes  were  tested  with  a  known  flow  of  water,  and  found 
to  give  results  within  5  per  cent.;  all  joints  must  be  perfectly  air 
tight."  If  the  velocity  of  the  upward  flow 
of  water  is  found  in  this  manner,  the  dis- 
charge is  readily  obtained  by  multiplying  the 
area  of  the  pipe  by  this  velocity,  care  being 
taken  that  all  the  measurements  are  express- 
ed in  the  same  unit,  preferably  feet. 

The  tube  wells  at  Plainfield,  N.  J.,  are  6 
inches  in  diameter  and  driven  from  35  to  50 
feet  into  a  bed  of  water-bearing  gravel.  The 
wells  were  not  driven  at  right  angles  to  the 
direction  of  the  underground  stream,  and  on 
this  account  but  partially  intercepted  the 
flow.  Inside  each  6-inch  tube,  which  is  per- 
forated at  the  bottom  in  the  usual  manner, 
there  is  a  4J-inch  suction  pipe  25  feet  long. 
This  inner  tube  is  attached  at  its  upper  end 
to  a  casting  fitting  on  top  of  the  outer  tube, 
a  rubber  gasket  being  used  to  make  the 
connection  tight.  The  casting  has  a  vent 
on  the  side  through  which  air  is  admitted 
to  the  space  between  the  two  tubes,  thus 
converting  the  well  into  an  open  well  so  far  as  the  work  of  pump- 
ing from  it  is  concerned.  The  top  of  the  casting  is  also  provided 
with  a  tap  by  which  a  vacuum  gauge  may  be  applied.  The  wells 
were  connected  with  a  wrought-iron  suction  main  from  8  to  12 
inches  in  diameter.  The  most  distant  well  is  500  feet  from  the 
pumps,  and  "shows  in  an  interesting  manner  by  the  vacuum  at  the 
well  head  and  increased  vacuum  at  the  pump,  the  effect  of  long 
suction  and  friction  in  the  main."  This  is  indicated  more  clearly 
by  some  figures  in  a  description  of  these  works  by  Mr.  L.  L.  Tri- 


CS  Inlet  Plug. 


FIGURE  26. 


1,4  WATER-WORKti    MANUAL. 

bus,  M.  Am.  Soc.  C.  E.,  in  Volume  xxxi.  of  the  "Transactions"  of 
the  American  Society  of  Civil  Engineers.  During  a  24-hour  test 
the  average  suction  lift  in  feet,  referred  to  the  level  of  the  upper 
pump  valves,  was  21.78  at  the  farthest  well  and  22.83  at  the  near- 
est, the  suction  in  the  air  chamber  being  26.16. 

This  plant,  like  many  others,  was  constructed  with  the  suction 
main  and  pumps  too  high.  During  a  season  of  long-continued 
dry  weather  the  water  level  became  so  low  that  difficulty  arose 
with  the  extreme  suction  lift  obtained,  from  20  to  28  feet,  accord- 
ing to  the  rate  of  pumping,  a  fall  of  some  6  or  7  feet  since  the 
earlier  observations,  so  it  was  deemed  best  to  lower  the  pumps  8 
feet  1  inch  below  their  first  positions. 

This  trouble  occurs  so  often  that  special  attention  should  be 
paid  to  avoiding  it  in  making  plans  for  the  work.  The  usual  ob- 
jection to  setting  pumps  and  mains  low  is  that  the  ground- water 
makes  the  work  of  excavating  difficult,  but  this  can  be  overcome 
by  strong  pumping  from  the  permanent  wells,  and,  if  necessary, 
temporary  ones  driven  in  such  a  manner  as  to  drain  the  site  of 
excavations. 

The  methods  of  sinking  driven  wells  are  numerous,  as  is  evi- 
dent from  what  has  been  said,  and  contractors  vary  in  their  pref- 
erence of  plans  for  work  in  the  same  locality.  Perhaps  the  most 
striking  instance  of  this  is  furnished  by  the  history  of  the  Lowell, 
Mass.,  wells,  which  is  here  condensed  from  the  annual  reports  of 
Mr.  George  Bowers,  City  Engineer: 

The  first  work  of  this  nature  was  the  sinking  of  seven  3-inch 
wells.  At  the  upper  end  of  a  wrought-iron  pipe,  19  feet  long,  a 
hose  was  attached,  which  was  connected  with  a  pump.  A  strong 
stream  of  water  was  forced  down  the  pipe  by  this  means,  cutting 
away  the  earth  so  as  to  allow  the  pipe  to  drop  gradually.  The 
water  and  excavated  material  came  to  the  surface  outside  the  pipe. 
When  the  first  length  had  been  driven  in  this  manner,  a  second 
was 'coupled  to  it,  and  the  process  continued  until  rock  was 
reached.  The  pipe  was  then  pulled  up  to  allow  water  to  enter  its 
lower  end,  and  it  was  finally  connected  with  a  pump,  which  was 
run  several  hours,  or  until  the  water  was  clear,  when  the  well  was 
ready  for  testing.  Samples  of  the  earth  washed  up  were  pre- 
served, together  with  notes  showing  the  depths  from  which  they 
came. 

The  second  set  of  wells,  which  were  3  inches  in  diameter,  had 


WATER-WORKS  MANUAL.  115 

perforated  lengths  covered  with  brass  gauze,  and  were  provided 
with  a  steel  shoe  at  the  lower  end  of  each  screen.  Such  a  combi- 
nation was  driven  a  short  distance  by  means  of  a  150-pound  drop- 
hammer,  and  the  earth  inside  washed  out  by  means  of  a  pipe  con- 
nected with  a  force  pump.  This  operation  was  repeated  every  5 
feet  until  the  well  was  driven.  A  dry-wood  plug  was  then 
swedged  into  the  steel  shoe. 

The  third  plant  consisted  of  6-inch  wells,  which  were  sunk  by 
means  of  a  sand-bucket  or  sand-pump  nearly  as  large  as  the  inside 
of  the  pipe  and  about  6  feet  long.  Such  a  bucket  is  merely  a 
cylinder  with  a  valve  opening  upward  at  the  bottom.  It  is 
churned  up  and  down  by  wooden  rods  connected  with  screw  coup- 
lings until  it  is  filled,  when  it  is  lifted  up  to  the  surface  and 
emptied.  A  large  pyramidal  frame  like  those  used  in  oil  well 
sinking  was  employed  at  Lowell.  The  bucket  removed  stones  5^ 
inches  in  diameter,  when  wells  were  driven  through  gravel.  While 
the  bucket  was  in  use,  the  pipe  was  gen.tly  turned  or  rocked,  and 
sunk  by  its  own  weight  in  sand;  in  very  hard  gravel  it  was  some- 
times driven  a  little  with  a  heavy  wooden  hammer.  Where  stones 
too  large  to  come  up  through  the  pipe  were  encountered,  they 
were  broken  with  a  large  drill,  or,  if  this  was  impossible,  the  pipe 
was  pulled  up  and  the  location  of  the  well  abandoned. 

Two  push  wells,  lying  almost  horizontal  under  the  surface,  were 
also  sunk  by  this  contractor.  They  were  driven  by  means  of  a 
strong  dam  or  bulkhead  to  press  against,  a  strong  clamp  on  the 
end  of  the  pipe,  and  four  jackscrews  between  the  bulkhead  and 
clamp.  This  proved  a  slow  and  expensive  plan,  but  enabled  a 
very  long  screen  to  be  placed  in  a  thin  water-bearing  stratum. 
Although  it  has  worked  satisfactorily  in  other  places,  the  addi- 
tional yield  of  water  did  not  pay  for  the  difference  in  cost  at 
Lowell. 

After  sinking  the  pipe  the  desired  depth,  the  depth  below  the 
surface  and  the  thickness  of  the  water-bearing  stratum  were  de- 
termined. The  tube  was  then  cleaned,  filled  with  water  to  hold 
back  the  sand,  and  a  strainer  of  proper  length  inserted  and  held 
in  position  by  means  of  wooden  rods.  The  pipe  was  next  pulled 
back  until  the  openings  on  the  strainer  were  exposed  to  the  water- 
bearing stratum.  A  swedge  block  was  finally  used  to  fasten  the 
lead  rim  or  joint  on  top  of  the  strainer  to  the  well  pipe.  The 
strainers  in  the  push  wells  were  24  and  42  feet  long  respectively, 


116  WATER-WORKS    MANUAL. 

while  those  in  the  vertical  wells  were  from  8  to  17  feet.  After 
they  were  swedged  into  the  pipe,  and  the  well  thoroughly  pumped 
and  washed  by  steam,  the  water  was  perfectly  clear  and  free  from 
sand. 

The  next  set  of  wells  were  for  test  purposes,  and  were  all  2 
inches  in  diameter.  Some  of  them  were  merely  open  pipes  down 
which  streams  of  water  were  forced  by  a  pump,  thus  forcing 
passages  into  which  the  pipes  dropped  of  their  own  weight  or 
under  light  blows.  The  remaining  wells  were  driven  without 
washing,  and  did  not  give  as  good  results  as  those  sunk  with 
water. 

Another  set  of  wells  was  driven  by  a  still  different  plan.  A 
pipe  was  started  in  the  ground  by  fastening  a  heavy  clamp  about 
it  firmly,  and  striking,  this  clamp  with  a  hammer  sliding  on  the 
pipe  and  furnished  with  four  handles,  by  which  it  could  be  lifted 
by  several  men.  As  the  sinking  progressed  the  clamps  would  be 
shifted  higher,  and  finally  the  pipe  was  firm  enough  to  allow  a 
platform  to  be  attached  to  it  about  6  feet  from  the  ground.  The 
men  stood  on  this  platform  and  their  weight  aided  the  driving. 
Moreover,  it  was  unnecessary  to  shift  the  clamp  so  often  with 
this  arrangement  as  where  the  men  stood  on  the  ground. 

AIK  IN  WELLS. 

The  greatest  difficulty  in  operating  a  driven-well  plant  is  due 
to  accumulations  of  air.  Some  of  this  air  enters  the  wells  with 
the  water,  but  most  of  it  probably  leaks  through  the  joints  of  the 
suction  and  branch  mains,  A  line  of  pipe  which  is  perfectly 
tight  under  hydraulic  pressure  may  nevertheless  leak  when  tested 
with  air.  Consequently  the  greatest  care  should  be  taken  to  have 
the  entire  system  of  wells  and  pipes  as  tight  as  it  can  be  made.  It 
is  hardly  less  imporant  to  have  as  few  bends  in  the  pipes  as  pos- 
sible, and  to  have  the  latter  so  large  that  the  water  will  flow 
through  them  at  a  low  velocity  and  with  correspondingly  slight 
friction.  Everything  should  be  done  to  reduce  to  a  minimum 
the  resistance  encountered  by  the  water  in  passing  from  the 
ground  to  the  pumps.  Some  engineers  believe  that  it  is  advisable 
on  this  account  to  connect  the  wells  with  the  suction  mains  by 
diagonal  branches,  which  deflect  the  course  of  the  water  some  45 
degrees  only,  instead  of  90  degrees  as  in  the  usual  method  of  con- 
nection. The  author  has  heard  less  complaint  about  air  in  plants 
with  small  suction  pipes  running  down  inside  the  main  well  tube 


WATER-WORKS    MANUAL.  117 

than  in  those  where  the  well  consists  of  a  single  tube,  which  is 
itself  connected  to  the  system  of  suction  pipes. 

The  construction  of  the  suction  pipe  is  very  important.  It 
should  consist  of  cast-iron  flange  pipe,  with  the  flanges  carefully 
trued.  In  one  exceptionally  tight  main  each  joint  was  made  with 
a  copper  gasket  placed  between  a  pair  of  rubber  gaskets.  Joints 
are  also  made  with  lead  rings  wrapped  about  with  lamp  cotton, 
or  covered  with  cloth  saturated  with  tar;  in  fact,  there  are  many 
ways  of  making  them,  although  that  first  mentioned  is  perhaps 
the  best.  The  branches  which  have  screw  couplings  should  have 
the  threads  cut  with  more  than  usual  care  to  secure  tightness,  and 
if  red  or  white  lead  is  employed,  it  should  be  used  sparingly. 
Each  well  should  have  a  gate  on  the  branch  leading  to  it,  and 
care  must  be  taken  that  the  gate  stem  is  tight.  A  patented  joint 
by  \vhich  a  connection  is  made  air-tight  by  forcing  lead  against 
the  screw  threads  by  means  of  a  set  screw  seems  particularly  use- 
ful on  the  screw-joints  of  a  driven-well  plant.  All  pipes  should 
be  laid  carefully  to  line  and  grade.  If  there  is  any  doubt  as  to 
the  stability  of  the  bed  on  which  they  rest,  they  should  be  sup- 
ported on  piles  or  cradles  which  will  ensure  safety  from  all  settle- 
ment. The  grade  or  drop  toward  the  wells  should  be  not  less 
than  6  inches  in  100  feet,  and  there  must  be  no  summits  or  bends 
of  any  sort  in  which  air  can  collect.  Another  point  to  be  taken 
into  consideration  is  the  protection  of  the  mains  from  the  sun. 
If  this  is  not  done  in  some  manner,  the  expansion  of  the  main 
suction  pipe  in  summer  may  be  the  cause  of  troublesome  leaks  in 
some  of  the  small  joints  toward  the  ends  of  the  line. 

The  mains  end  in  air  separators,  which  are  chambers  where  the 
air  is  liberated  from  the  water  and  removed  through  pipes  run- 
ning to  wet  vacuum  pumps.  There  are  many  forms  of  these  sep- 
arators, each  contractor  having  his  favorite.  He  is  usually  de- 
cidedly averse  to  explaining  its  details,  but  willing  to  install  it 
under  good  guarantees  that  it  will  work  satisfactorily.  It  is  not 
surprising,  therefore,  that  little  information  concerning  them  has 
thus  far  been  published.  Many  are  automatic  in  action  and  actu- 
ated by  a  float  in  the  upper  part  of  the  separator.  As  the  air  col- 
lects the  float  naturally  settles  with  the  depression  of  the  water 
level  in  the  chamber.  When  it  has  fallen  a  certain  amount  it 
opens  the  throttle  valve  of  the  vacuum  pump  in  one  way  or  an- 
other. If  the  air  comes  in  faster  than  the  pump  removes  it,  the 


118  WATER-WORKS    MANUAL. 

float  sinks  farther,  and  adjusts  the  throttle  so  as  to  give  the  pump 
a  greater  speed.  When  the  air  is  removed  the  float  rises,  and 
closes  the  throttle  in  so  doing. 

Many  separators  have  no  such  automatic  features.  Some  of 
them  are  merely  large  chambers  with  a  smaller  chamber  on  top 
provided  with  a  gauge  glass  by  which  the  amount  of  air  within 
can  be  readily  determined.  The  engineer  in  charge  fixes  the 
speed  of  the  vacuum  pump  by  observing  the  gauge,  and,  as  the 
amount  of  air  carried  by  the  water  from  the  same  battery  of  wells 
does  not  vary  very  much,  such  separators  answer  fairly  well. 

A  separator  used  by  William  D.  Andrews  &  Brother  on  driven- 
well  plants  built  by  them  is  probably  among  the  simplest  that  can 
be  employed,  and  possesses  the  additional  merit  of  having  worked 
for  a  number  of  years  with  complete  satisfaction  to  the  engineers 
in  charge  of  the  plants.  It  depends  for  its  action  upon  the  fact 
that  water  cannot  be  raised  by  suction  more  than  about  34  feet 
theoretically;  practically,  several  feet  less.  It  is  a  large  vertical, 
cylindrical,  sheet-iron  tank  or  chamber  on  top  of  which  is  a  much 
smaller  one,  perhaps  6  inches  high,  and  rising  from  the  top  of  the 
latter  is  a  pipe  about  3  inches  in  diameter.  This  runs  to  an  ele- 
vation of  about  35  feet  above  the  level  of  the  upper  pump  valves. 
The  air  collects  in  this  pipe,  which  is  closed  at  the  top,  and  is  re- 
moved through  a  smaller  pipe  running  up  within  it  nearly  to  its 
top.  The  inner  pipe  is  connected  with  the  air  pump,  and  on  ac- 
count of  the  height  at  which  air  enters  it,  comparatively  little  if 
any  water  is  mingled  with  the  air.  The  outside  vertical  pipe  has 
to  be  guyed  securely  and  does  not  present  a  particularly  attractive 
appearance,  but  these  are  the  only  objections  against  this  plan,  so 
far  as  the  author  has  been  able  to  learn. 

The  air  separator  used  on  the  first  permanent  driven-well  plant 
at  Lowell,  Mass.,  was  designed  by  Mr.  B.  0.  Gage,  and  is  described 
substantially  as  follows  in  a  report  by  Mr.  George  Bowers,  City 
Engineer  of  that  place.  It  is  on  the  suction  main  just  outside 
the  pumping  station,  is  circular  in  plan  and  made  of 
boiler  iron.  It  is  dome-shaped,  28  inches  high  at  the  side,  44 
inches  in  the  center,  and  contains  three  dams.  The  water  com- 
ing from  the  wells  passes  over  the  first  dam,  under  the  second, 
over  the  third  and  thence  into  the  pipe  running  to  the  pump.  A 
6x8.5x6-inch  wet  vacuum  duplex  pump  was  connected  with  the 
top  of  the  separator  to  take  away  the  air  liberated  as  the  water 


WATER-WORKS    MANUAL.  112 

flowed  over  the  dams,  but  it  proved  too  small  and  a  7.5x10.25x10- 
inch  pump  was  put  to  work  with  the  first.  After  a  two-months' 
trial  of  the  separator,  the  middle  dam  was  removed,  with  good  re- 
sults. As  the  plant  is  composed  of  5,806  feet  of  suction  pipe  and 
branches,  there  is  a  great  number  of  joints  to  be 'kept  tight,  and  it 
requires  constant  care.  A  man  goes  over  the  line  every  morning 
with  a  pail  of  asphaltum  paint,  and  if  there  are  any  leaks  he  re- 
pairs them. 

WELL  SPECIFICATIONS. 

Through  the  courtesy  of  Mr.  Freeman  C.  Coffin,  M.  Am.  Soc. 
C.  E.,  the  writer  is  enabled  to  close  his  portion  of  the  discussion 
of  underground  supplies  with  a  number  of  extracts  from  the 
specifications  of  the  Wellesley  Water- Works  new  well  plant, 
which  was  designed  by  Mr.  Coffin: 

" Wells. — The  wells  are  to  be  of  2-J-inch  wrought-iron  pipe;  this 
pipe  will  be  furnished  in  approximately  5-foot  lengths,  with  screw 
threads  cut  on  both  ends  and  a  drive-well  coupling  furnished 
with  each  piece.  The  piece  for  the  lower  end  of  the  well,  or 
point,  will  be  furnished  ready  for  driving.  In  driving  the  wells 
the  washing  out  process  by  water  pressure  shall  be  employed. 
The  contractor  shall  provide  a  suitable  plant  for  this  purpose. 
Men  skilled  in  this  class  of  work  shall  be  employed.  Whenever 
the  engineer  shall  require  it,  a  diaphragm  pump  shall  be  attached 
to  the  top  of  the  well  and  a  test  made  of  its  capacity.  Each  well 
shall  be  driven  to  a  depth  where  the  most  satisfactory  flow  of 
water  can  be  obtained.  No  well  will  be  connected  with  a  depth 
of  less  than  28  feet  from  the  surface  of  the  ground  to  the  top  of 
the  holes  in  the  point.  Any  well  driven  by  the  orders  of  the  en- 
gineer, if  abandoned,  will  be  paid  for  at  the  regular  rate,  and  the 
contractor  will  be  required  to  remove  the  pipe  at  his  own  ex- 
pense, care  being  taken  not  to  injure  it  by  such  removal. 

"The  joint  will  be  made  with  the  material  (elastic  cement  or 
otherwise)  furnished  by  the  committee. 

"After  each  well  is  driven  to  the  proper  depth  it  shall  be 
pumped  from  at  its  full  capacity  until  no  sand  or  gravel  rises  with 
the  water. 

"Well  Connections. — The  contractor  shall  do  all  trenching  and 
back-filling  and  furnish  all  necessary  lumber  for  sheeting  and 
bracing  at  his  own  expense.  The  top  of  each  well  shall  be  cut  off 
to  receive  the  long-bend  T-branch,  6  inches  lower  than  the  center 


123  WATER-WORKS    MAX  UAL. 

of  the  main  to  which  it  is  to  be  connected.  A  screw  thread  shall 
\)e  cut  on  the  top  of  the  pipe  1J  inches  long;  this  thread  shall  be 
made  with  great  care,  and  shall  make  an  air-tight  joint  with  the 
T-branch.  The  contractor  shall  be  required  to  cut  a  similar 
thread  upon  one  end  of  the  short  horizontal  piece  of  pipe  which 
connects  the  T-branch  to  the  gate.  The  connection  between  the 
well  and  the  main  will  be  finally  closed  by  making  the  joint  be- 
tween the  companion  flanges  on  the  2^-inch  gate.  All  of  the 
screw  and  flange  joints  on  this  connection  shall  be  perfectly  air- 
tight. 

"Suction  Mains. — The  contractor  shall  do  all  the  necessary 
trenching  and  back-filling,  shall  furnish  all  the  lumber  required 
for  sheeting  and  bracing,  and  for  the  permanent  platform  and 
blocking  under  the  pipe,  as  shown  on  the  detail  drawings.  The 
lumber  shall  be  good  sound  spruce  acceptable  to  the  engineer. 
He  shall  lay  the  pipe  to  the  grades  given  by  the  engineer  approxi- 
mately as  shown  on  the  profile.  All  of  the  joints  in  these  lines 
shall  be  run  with  pure  lead  and  carefully  calked.  The  lead  in 
the  joints  of  the  12  and  16-inch  pipe  shall  be  2J  inches  deep,  and 
in  the  6  and  8-inch  pipe  2  inches  deep.  All  joints  must  be  air- 
tight. In  making  these  joints  the  water  in  the  trench  must  be 
pumped  down  to  the  bottom  of  the  platform  and  kept  there  until 
they  are  all  calked. 

"Running  Joints. — Before  running  the  lead  the  joints  shall  be 
carefully  wiped  out  to  make  them  clean  and  dry;  the  joint  shall 
be  run  full  at  one  pouring,  and  the  melting  pot  shall  always  be 
kept  within  50  feet  of  the  joint  about  to  be  poured. 

"Extra  Foundations. — If  in  laying  these  mains  the  foundation 
in  any  part  of  the  trench  should  be  found  to  be  unsuitable  in  the 
opinion  of  the  engineer,  the  contractor  shall  put  in  such  founda- 
tion as  the  engineer  may  direct,  and  for  such  and  all  other  extra 
work  shall  be  entitled  to  be  paid  the  actual  cost  thereof,  and  15 
per  cent.,  additional  for  contractor's  profit,  use  of  tools  and  gen- 
eral superintendence. 

"Tests. — Each  section  of  the  suction  main  and  of  the  well  con- 
nections as  far  as  the  2^-inch  gate  shall  be  tested  in  the  following 
manner: 

"The  section  to  be  tested  shall  be  shut  off  by  the  gate  at  each 
end;  an  air-pump  shall  be  connected  with  the  main.  The  trench 
shall  be  filled  with  clean  water,  either  by  infiltration  from  the 


WATER-WORKS    MANUAL.  121 

ground  or  directly  from  the  brook.  An  air  pressure  of  50  pounds 
per  square  inch  shall  be  applied  to  the  mains  and  maintained  as 
long  as  the  engineer  may  direct.  If  this  pressure  can  be  main- 
tained without  pumping,  the  work  will  be  considered  tight  and 
satisfactory.  If  it  is  necessary  to  run  the  pump  to  maintain  the 
pressure,  search  shall  be  made  for  the  leakage,  which  must  be 
found  and  repaired  in  a  manner  satisfactory  to  the  engineer.  The 
contractor  shall  furnish  all  men,  tools  and  materials  to  make  these 
tests  at  his  own  expense.  They  shall  be  made  under  the  direction 
of  the  engineer,  and  continued  until  he  is  satisfied  of  the  tight- 
ness of  the  work.  No  back-filling  of  trenches  or  removal  of 
sheeting  or  bracing  will  be  allowed  until  each  section  is  tested 
and  orders  to  that  effect  are  given  by  the  engineer. 

"  Work  to  be  Kept  in  Kepair. — The  contractor  shall  keep  the 
work  in  good  repair  for  the  term  of  six  months  after  the  date  that 
the  water  is  let  into  the  piping  for  the  purposes  contemplated  in 
building  said  works,  and  shall  correct  and  repair  promptly  during 
all  that  time  all  the  leaks  and  failures  of  whatever  description, 
and  all  settlements  and  irregularities  of  surfaces  of  streets  and 
lines,  the  work  in  all  respects  to  be  in  good  condition  at  the  end 
of  that  time. 

"Wrought-i ron  Pipe. — The  pipe  shall  be  the  best  quality  of 
American  wrought-iron  lap-welded  pipe  of  the  standard  weight 
(or  extra  heavy,  according  to  circumstances).  Each  length  as  it 
comes  from  the  mill  shall  be  cut  into  four  pieces  of  approximately 
o  feet  each.  The  cutting  shall  be  done  by  machine  in  such  a 
manner  that  the  ends  of  the  pipe  shall  be  smooth,  true,  and  at 
right  angles  with  the  axis  of  the  pipe.  Each  piece  of  pipe  shall  be 
straight  and  true  throughout  its  length.  A  standard  2  J-inch  iron 
pipe  screw  shall  be  cut  on  each  end  of  each  pipe;  these  screws 
shall  be  cut  by  machine,  shall  be  interchangeable,  and  shall  so 
perfectly  fit  the  taper  and  thread  of  the  driven  well  coupling  that 
the  ends  of  the  two  pieces  shall  screw  up  close  to  each  other  in  the 
centre  of  the  coupling,  and  at  the  same  time  make  a  perfectly 
tight  fit  in  the  thread.  This  thread  must  be  cut  true  with  the 
pipe,  so  that  when  two  pieces  are  screwed  into  one  coupling  their 
axes  shall  be  in  the  same  straight  line. 

"Well  Points. — These  points  shall  be  approximately  five  feet 
in  length.  A  screw  thread  shall  be  cut  upon  one  end  the  same  as 
on  the  ordinary  pipe  lengths  specified  above.  There  will  be  48 


122  WATER-WORKS    MANUAL. 

holes  drilled  and  tapped  in  the  other  end  of  the  pipe  and  bushed 
with  one-fourth -inch  brass  pipe,  iron  pipe  size,  as  shown  in  the 
detail  drawings.  This  pipe  to  be  threaded  and  screwed  into  the 
holes  in  the  iron  pipe,  cut  off  with  about  one-sixteenth-inch  pro- 
jection from  either  wall  of  the  pipe  and  neatly  headed  down  with 
a  light  hammer.  A  swage  of  a  form  satisfactory  to  the  engineer 
shall  be  used  on  the  inside  for  heading  the  bushing. 

"The  2J-inch  pipe  for  this  point  shall  be  the  best  quality 
American  wrought-iron  lap-welded  pipe,  extra  heavy. 

"Couplings. — The  couplings  shall  be  of  the  drive-well  pattern, 
so  called,  similar  to  the  sample  in  the  office  of  the  engineer.  They 
shall  have  a  sound,  whole,  clean-cut  thread  of  2^-inch  iron  pipe 
standard.  The  ends  shall  be  reamed  out  about  three-eighths- 
inch  deep,  large  enough  to  just  receive  the  outside  of  the  un- 
threaded pipe.  The  total  length  of  the  coupling  shall  be  3£ 
inches. 

"Testing  Gates. — All  of  this  work  (gates)  is  to  be  used  under  a 
vacuum  and  careful  tests  must  be  made  of  each  gate.  These 
tests  must  be  made  by  closing  the  valves  to  their  seats,  connect- 
ing an  air  pump  or  air  pressure  to  the  body  of  the  gates  and  im- 
mersing the  entire  gate  in  clear  water.  One  hundred  pounds  air 
pressure  shall  be  applied.  The  gates  shall  sustain  this  pressure 
without  showing  a  sign  of  air  leakage.  The  valves  shall  then  be 
opened  wide  and  closed  three  times  and  the  pressure  applied  again 
to  discover  if  the  movement  of  the  stem  causes  leakage  in  the 
stuffing  box. 

"The  2-|-inch  gates  and  flanges  shall  be  tested  by  screwing 
plugs  into  both  ends  and  applying  the  pressure,  both  with  the 
valve  open  and  shut,  the  gate  to  be  entirely  under  water  at  the 
time;  the  companion  flange  to  be  connected  at  time  of  test. 

"If  leakage  is  discovered  in  any  part  of  the  gates,  it  shall  be 
optional  with  the  engineer  whether  to  have  it  corrected  or  to  re- 
ject the  gate." 


CHAPTER  XI.— DEEP  AND  AETESIAN  WELLS. 

THE  geological  features  of  deep  and  artesian  wells  have  been 
fully  described  in  a  paper  by  Prof.  Thomas  C.  Chamberlain,  en- 
titled "The  Eequisite  and  Qualifying  Conditions  of  Artesian 
Wells,"  published  in  the  Fifth  Annual  Eeport  of  the  United 
States  Geological  Survey.  This  paper  is  the  most  complete  pres- 
entation of  the  subject  in  English  with  which  the  author  is  fa- 
miliar,, and  most  of  it  applies  equally  well  to  non-flowing  deep 
wells.  As  these  reports  can  now  be  consulted  in  most  public 
libraries,  no  attempt  will  be  made  here  to  present  more  than  a 
mere  outline  of  this  phase  of  the  subject. 

The  only  way  in  which  water  can  pass  in  any  marked  quantity 
through  close-textured  rocks  is  by  means  of  fissures  or  channels 
formed  by  solution.  Such  rocks  are  those  of  the  crystalline,  lime- 
stone and  clay  classes,  such  as  granite,  greenstone,  hard  limestone 
and  shales.  While  they  may  be  full  of  cracks  and  crevices  on 
weathered  surfaces,  they  are  generally  homogeneous  at  moderate 
depths,  and  there  is  little  likelihood  of  securing  water  from  them. 
Limestones  near  the  surface  are  often  hollowed  out  into  large 
passages  by  the  dissolving  action  of  water  passing  through  them, 
but  this  action  is  chiefly  found  where  the  limestone  is  not  over- 
lain by  other  rocks.  Limestones  that  were  once  channeled  in 
this  manner  and  afterward  covered  with  a  thick  mantle  of  clay 
have  been  found  to  yield  a  good  supply,  but,  as  a  rule,  fine- 
grained limestone  is  a  poor  rock  in  which  to  look  for  much  water 
of  a  quality  fit  for  domestic  and  boiler  uses.  Beds  of  sand,  gravel, 
sandstone,  conglomerate,  porous  chalk  and  coarse,  granular  lime- 
stone are  the  rocks  in  which  water  is  generally  found.  Naturally 
the  best  confining  strata  are  those  least  pervious  to  water,  such 
as  clay,  clay  shale,  shale  limestone,  shale  sandstones  and  the  vari- 
ous crystalline  rocks. 

The  upper  and  lower  confining  strata  are  not  of  equal  import- 
ance, and  fissures  may  exist  without  detriment  in  the  stratum  be- 


124  WATER-WORKS    MANUAL. 

low  the  porous  bed  which  would  have  serious  consequences  in  that 
above.  Fissures  in  the  lower  confining  bed  will  rarely  cause 
trouble  unless  they  open  into  a  porous  stratum  still  lower,  which 
has  an  outcrop  at  a  lower  elevation  than  the  top  of  the  well.  In 
such  a  case  the  water  will  escape  through  this  outcrop  and  will 
not  flow  out  of  the  well,  which  will  become  of  the  non-flowing 
type  in  spite  of  the  fact  that  its  top  may  be  much  below  the  out- 
crop or  gathering  ground  of  the  main  porous  bed. 

There  is  one  feature  to  be  observed  in  connection  with  the  up- 
per confining  stratum  which  modifies  in  a  measure  the  effect  of 
permeability  in  this  bed.  If  the  stratum  is  overlain  with  material 
in  which  the  natural  ground-water  surface  is  at  about  the  same 
elevation  as  the  collecting  area  of  the  water-bearing  stratum  to 
be  tapped  by  the  well,  the  upper  confining  stratum  may  be  some- 
what permeable  and  yet  not  permit  the  passage  of  the  artesian 
water  owing  to  the  hydrostatic  pressure  exerted  on  it  from  above. 
The  lower  the  ground-water  surface  is  below  the  elevation  of  the 
outcrop  of  the  porous  stratum,  the  greater  is  the  effect  of  per- 
meability in  the  upper  confining  stratum. 

There  is  always  some  chance  of  failure  in  attempting  to  secure 
an  artesian  supply  from  a  water-bearing  stratum  which  outcrops 
not  far  from  the  well  at  a  much  lower  elevation  than  the  surface 
where  the  well  is  sunk.  Nevertheless,  the  frictional  resistance 
of  the  stratum  to  the  flow  of  water  from  the  site  of  the  well  to 
the  lower  outcrop  may  be  so  great  that  the  water  will  rise  to  the 
top  of  the  well.  "Several  important  wells  at  Oshkosh,  Fond  du 
Lac,  Watertown  and  Palmyra,  Wis.,  flow  from  formations  that 
outcrop  within  50  miles  at  notably  lower  levels.  These  outcrops, 
however,  are  not  in  the  line  of  slope  from  fountain  head  to  well, 
but  more  nearly  along  the  line  of  strike  at  right  angles  to  it.  All 
these  wells  probably  owe  their  success  to  the  high  subterranean 
water  level  between  the  wells  and  their  sources,  but  resistance  to 
flow  through  the  water-bearing  bed  seems  also  to  serve  an  import- 
ant function,  unless  the  entire  head  would  be  relieved  through 
the  low  outcrops." 

When  the  topographical  and  geological  conditions  have  been 
determined,  after  careful  consideration,  to  be  favorable  for  the 
construction  of  a  deep  or  artesian  well,  it  is  necessary  to  ascertain 
how  many  wells  in  the  vicinity  reach  to  the  stratum  it  is  pro- 
posed to  tap,  and  how  they  affect  one  another.  If  the  starting 


WATER-WORKS  MANUAL.  125 

of  a  well  causes  much  diminution  in  the  discharge  of  others  in  the 
neighborhood  it  is  an  indication  that  about  all  the  available  water 
in  the  porous  stratum  is  already  being  drawn  from  it.  Another 
well  may  so  diminish  the  flow  from  those  previously  constructed 
that  serious  inconvenience  may  arise.  If,  however,  the  starting 
of  one  well  has  little  or  no  influence  on  those  about  it,  one  more 
may  be  sunk  with  fair  assurance  that  it  will  not  be  a  source  of 
vexation. 

It  is,  of  course,  desirable  to  sink  the  well  some  distance  into  the 
porous  stratum  so  that,  by  perforations  in  the  lower  portion  of 
the  pipe,  the  water  may  enter  the  well  through  a  much  larger 
surface  than  is  offered  by  the  cross-section  of  the  pipe  itself.  In 
case  the  flow  remains  inadequate  after  the  well  has  been  sunk  far 
into  the  water-bearing  stratum,  various  expedients  may  be  tried 
to  increase  it.  One  of  these  is  the  explosion  of  a  torpedo  at  the 
bottom  of  the  well.  This  rends  and  shatters  the  rock,  and  opens 
fissures  through  which  the  water  may  pass  more  freely  to  the  well. 
It  is  a  common  practice  in  the  Pennsylvania  oil  regions,  but  has 
not  been  adopted  very  often  in  developing  water  supplies,  al- 
though equally  well  adapted  to  such  work. 

The  usual  method  of  increasing  the  flow  of  a  well  is  to  ream  it 
to  a  larger  diameter.  This  is  more  expensive  than  shooting  it 
with  a  torpedo,  but  it  has  advantages  worth  noticing,  as  the  first 
bore  need  be  only  a  small  one,  easy  to  drill  and  involving  a  com- 
paratively small  loss  if  it  has  to  be  abandoned  from  failure  to 
strike  water.  "From  the  character  of  the  flow  obtained  by  the 
first  operation  it  is  possible  to  anticipate  what  will  be  the  prob- 
able result  of  the  enlargement.  If  the  water  issues  with  great 
force  it  is  manifest  that  the  larger  bore  will  greatly  increase  the 
delivery,  because,,  in  addition  to  the  increased  size,  the  friction  is 
relatively  less.  If  the  flow  be  gentle  and  the  head  known  to  be 
high,  it  is  clear  that  the  conveying  stratum  must  interpose  ob- 
stacles, and  the  indications  are  unfavorable  to  a  very  great  in- 
crease from  the  enlarged  well.  If  the  fountain-head  is  low,  a  full, 
gentle  flow  is  the  natural  sign  of  a  generous  stream,  which  might 
give  an  almost  equally  flush  discharge  from  the  enlarged  bore.'7 

These  considerations  also  govern  the  choice  between  one  large 
and  several  small  wells.  If  it  is  known  that  the  water-bearing 
stratum  will  afford  a  large  supply,  then  a  large  well  will  probably 
be  satisfactory.  If  there  is  any  uncertainty  as  to  the  character 


126  WATER-WORKS    MANUAL. 

of  the  stratum,  it  will  probably  be  desirable  to  use  a  number  of 
small  wells,  driven  far  enough  apart  to  tap  an  extensive  area  of 
water-bearing  rock.  If  these  are  shot  with  torpedoes  it  is  evi- 
dent that  they  will  draw  water  from  a  far  greater  portion  of  the 
stratum  than  a  single  well  of  any  reasonable  diameter.  If  a  num- 
ber of  wells  are  employed  it  is  preferable  to  locate  them  on  a  line 
at  right  angles  to  the  direction  in  which  the  water  flows  in  the 
porous  stratum,  or  along  a  line  somewhat  convex  toward  the  di- 
rection of  the  flow.  The  latter  plan  is  probably  the  better,  as  it 
tends  to  increase  the  discharge  from  the  wells  on  the  ends  of  the 
line. 

SINKING  WELLS. 

The  methods  of  sinking  wells  to  considerable  depths  may  bo 
classed  under  percussion,  diamond  and  rotary  drilling. 

The  percussion  drilling  is  merely  an  elaboration  of  hand  drill- 
ing and  in  its  simplest  form,  using  a  spring  pole,  it  has  been  em- 
ployed for  many  centuries.  Although  drilling  machinery  is  now 
supplied  at  low  cost  by  a  number  of  manufacturers,  the  spring 
pole  nevertheless  may  prove  useful  in  sinking  wells  to  depths  of 
200  to  250  feet.  The  following  description  of  the  method  of 
using  such  an  outfit  presupposes  some  knowledge  of  artesian  well 
sinking,  which  is  readily  acquired  from  Trautwine's  "Pocket 
Book"  or  the  catalogue  of  any  manufacturer  of  well-sinking  ap- 
paratus. 

The  spring  pole  is  generally  a  sound,  round  pine  pole  about  30 
feet  long,  10  inches  in  diameter  at  the  butt  and  6  inches  at  the 
tip.  It  is  firmly  embedded  in  the  ground  in  an  inclined  position, 
with  its  free  end  over  the  spot  chosen  for  the  well.  It  is  usual  to 
sink  a  shaft  a  number  of  feet  from  the  surface,  because  it  is 
cheaper  to  do  this  than  to  drive  a  well  the  same  number  of  feet  at 
the  end  of  the  work,  and  also  because  a  pit  below  the  platform  on 
the  surface  enables  the  operations  to  be  conducted  more  rapidly. 
Three  inches  is  about  the  greatest  diameter  of  wells  sunk  in  this 
manner,  and  the  method  is  accordingly  useful  only  where  small 
supplies  are  desired. 

After  the  spring  pole  has  been  erected,  a  shaft  excavated  to  a 
depth  of,  say,  8  feet,  and  a  windlass  provided  on  the  platform  at 
the  top  of  the  shaft,  it  is  usually  necessary  to  drive  a  casing  pipe 
to  the  rock.  This  is  done  by  means  of  a  heavy  iron-bound  wood- 
en hammer,  about  4  feet  long,  18  inches  in  diameter  at  the  bot- 


WATER-WORKS    MANUAL  127 

torn  and  12  inches  at  the  top,  with  handles  for  guiding  it.  A 
rope  is  attached  to  the  end  of  the  spring  pole  and  the  hammer  is 
hung  from  it  by  a  hitch  easily  loosened  when  it  is  desired  to  shift 
the  position  of  the  hammer.  A  section  of  pipe  about  6  feet  long 
is  then  provided  with  an  annular  shoe  at  the  bottom  and  a  solid 
cap  at  the  top.  It  is  guided  by  blocks  and  sunk  as  far  as  possible 
by  the  hammer,  the  spring  pole  lifting  the  latter  and  thus  greatly 
diminishing  the  work  to  be  done  by  the  men.  After  driving  6  or 
8  inches  the  knot  by  which  the  hammer  is  hung  from  the  pole  is 
loosened  and  the  latter  lowered  to  within  an  inch  or  so  of  the  cap. 
In  this  way  little  strength  is  expended  uselessly  in  overcoming 
the  spring  of  the  pole.  When  the  top  of  the  pipe  has  been  sunk 
to  within  6  inches  of  the  surface,  the  cap  is  removed,  the  thread 
of  the  pipe  oiled  and  another  length  screwed  to  it.  This  length 
is  forced  down  in  the  same  manner  as  the  first,  and  the  process 
repeated  until  rock  is  reached.  It  is  generally  necessary  to  assist 
the  driving  every  few  feet  by  removing  the  soil  within  the  pipe 
with  an  earth  auger.  This  is  screwed  into  the  earth  as  far  as  it 
will  go  by  means  of  a  long  shank  to  which  pieces  may  be  connect- 
ed as  the  depth  increases.  When  the  auger  is  full  it  is  pulled  to 
the  surface  and  its  load  dumped.  The  casing  can  be  drawn  out 
of  the  hole,  if  desired,  by  a  clamp  at  its  top  against  which  a  couple 
of  jackscrews  are  operated. 

After  the  pipe  has  reached  rock  a  string  of  tools  ending  in  a 
drill  bit  is  lowered  to  within  a  few  inches  of  the  bottom  and  sus- 
pended from  the  spring  pole.  The  string  is  then  churned  up  and 
down,  and  the  rock  gradually  pounded  away  on  the  line  of  the 
hole.  It  is  generally  necessary  to  ream,  the  hole  true  after  it  has 
been  driven  with  the  bit;  the  reamer  is  operated  in  the  same  man- 
ner as  the  drill.  The  splinters  of  rock  are  removed  by  a  sand 
bucket  whenever  it  is  apparent  they  are  interfering  with  the  ac- 
tion of  the  tools.  Unless  the  bore  hole  contains  water.  enough 

*  o 

must  be  poured  into  it  to  give  a  depth  of  several  feet,  or  progress 
will  be  slow.  If  it  is  desired  to  continue  the  casing  into  the  rock, 
it  will  be  necessary  to  enlarge  the  bore  hole  with  an  expansion 
drill.  About  six  feet  a  day  is  said  to  be  a  fair  day's  work  in  hard 
sandstone  with  such  a  rig.  A  full  description  of  the  tools  re- 
quired and  the  methods  to  be  followed  will  be  found  in  a  paper 
by  Mr.  Edgar  G.  Tuttle  in  the  "School  of  Mines  Quarterly"  for 
November,  1894. 


128  WATER-WORKS    MANUAL. 

The  apparatus  just  described  is  the  simplest  that  can  be  em- 
ployed in  sinking  a  deep  well.  It  has  been  modified  in  many  ways 
by  replacing  the  pole  by  a  system  of  levers  or  cams  operated  by 
horse  or  steam  power.  The  best  way  to  obtain  information  con- 
cerning the  apparatus  is  to  write  for  the  catalogues  of  the  various 
manufacturers  whose  business  cards  appear  in  the  advertising 
columns  of  "The  Engineering  Record."  Engineers  having  access 
to  the  publications  of  the  Second  Geological  Survey  of  Pennsyl- 
vania will  find  a  particularly  good  description  of  well-sinking  in 
Mr.  John  F.  CarPs  report  on  "Oil  Regions." 

Diamond  drilling  is  done  by  means  of  a  tube  having  a  boring 
head  at  the  base,  set  with  small  pieces  of  diamond.  Water  is 
forced  down  the  tube,  which  is  pressed  against  the  rock  and  ro- 
tated. In  this  -maimer  a  hole  may  be  drilled  to  great  depths,  and, 
as  the  boring  head  leaves  a  core  of  rock,  it  is  possible  to  obtain 
from  it  a  very  good  idea  of  the  character  of  the  strata  penetrated. 
Much  the  same  plan  has  been  adopted  in  some  recently  built  ma- 
chines for  sinking  wells  in  earth;  these  machines  are  known  as  the 
rotary  or  rotary- jetting  type,  and  their  use  is  indicated  in  the  fol- 
lowing paragraph. 

The  method  of  sinking  the  wells  of  the  Natchez,  Miss.,  water- 
works was  to  put  in  a  casing  first  to  exclude  the  surface  water, 
and  then  commence  with  pipe  of  the  desired  size  and  force  it 
nearly  through  a  40-foot  bed  of  water-bearing  sand  about  260  feet 
below  the  surface.  Mr.  P.  K.  Yates,  M.  Am.  Soc.  C.  E.,  states 
that  the  pipe  had  a  notched  cutting  edge  and  gradually  wore  its 
way  down  by  being  revolved  by  a  suitable  machine.  Water  was  con- 
tinually pumped  down  the  center  of  the  pipe,  washing  out  all  the 
material  within  and  driving  it  to  the  surface  on  the  outside  of  the 
pipe.  Hard  material  was  sometimes  encountered,  when  drills 
would  be  dropped  down  the  pipe  and  the  obstruction  drilled 
through.  The  pipe  had  to  be  pulled  up  occasionally  to  put  on  a 
new  cutting  edge;  hydraulic  jacks,  connected  with  powerful 
pumps,  were  used  for  this  purpose.  After  a  pipe  was  in  place,  a 
strainer  20  feet  long  was  dropped  into  it  and  the  pipe  pulled  up 
that  distance,  the  strainer  remaining  in  the  sand.  A  patented 
connection  was  then  made  to  prevent  any  water  entering  the  pipe 
except  through  the  strainer. 

SPECIFICATIONS. 

Most  wells  are  now  sunk  by  contract;  the  following  extracts 


WATER-WORKS    MANUAL. 


129 


from  the  specifications  of  the  Galveston  Water- Works,  prepared 
by  Mr.  Wynkoop  Kiersted,  M.  Am.  Soc.  C.  E.,  are  here  given  aa 
suggestive  for  such  documents: 

"The  location  of  each  and  all  of  the  wells  mast  be  submitted 
to  the  engineer  and  receive  his  approval  before  any  well  is  bored. 
The  depth  of  each  well  will  be  such  as  shall  be  determined  by  the 
engineer  at  the  time  of  boring  it. 

"The  plans  for  the  conduit  and  for  the  lateral  pipes  and  at- 
tachments will  be  prepared  by  the  engineer  as  soon  as  the  num- 
ber and  economic  distribution  of  the  wells  are  determined  by 
means  of  tests  hereafter  specified. 

"The  casing  to  be  used  for  the  artesian  wells  shall  be  what  is 
known  as  lap-welded  drive  pipe  of  the  following  minimum 
weights  and  thicknesses: 


inches  inside  diameter 


Thk 
nes 
.   i3lr 

;k- 

s. 
ich 

Weight 
per  foot. 
25  pounds. 
35 
44 
52 
58 
67 
72 

?,» 

« 

« 

« 

T 

\? 

6 

8 

10 
12 
13 
14 
15 

"The  thicl  ness  of  pipe  metal  shall  be  calipered.  No  pipe  of 
less  inside  diameter  than  6  inches  to  be  used.  The  couplings 
shall  be  of  the  best  wrought-iron,  lap-welded,  drive-pipe  sleeve 
sockets.  Both  pipe  and  sockets  sha.ll  be  fitted  with  perfect  V- 
shaped  threads,  not  more  than  eight  to  an  inch,  and  tapered  so 
that  the  pipes  shall  butt  against  each  other  when  screwed  up.  All 
inside  burrs  shall  be  removed.  Every  pipe  shall  be  perfectly 
straight  and  round  and  free  from  blisters.  The  metal  shall  be  of 
the  best  quality  of  wrought  iron,  suitable  for  perfect  threads 
being  cut  thereon.  In  sinking  the  wells  the  openings  between  the 
pipe  circumference  caused  by  sinking  a  small  pipe  inside  of  a 
larger  one  shall  be  completely  closed,  so  as  to  prevent  the  en- 
trance of  sand  and  water. 

"Each  well  shall  have  a  strainer  of  perforated  brass,  or  of  other 
equally  as  good  non-corrosive  material  acceptable  to  the  engineer, 
of  such  length  as  shall  be  best  suited  to  the  depth  of  the  sand 
stratum.  The  clear  strainer  opening  must  have  a  combined  area 
of  not  less  than  ten  times  the  inside  area  of  the  strainer  cross-sec- 
tion. The  size  of  the  openings  shall  be  graded  with  respect  to 
the  coarseness  of  the  sand  in  such  a  manner  as  to  exclude  sand 


130  WATER-WORKS    MANUAL. 

but  freely  permit  the  flow  of  water.  The  thickness  of  the  metal 
#t  any  point  in  the  body  of  the  strainer  shall  not  be  less  than  one- 
•eighth  inch,,  and  otherwise  the  strainer  shall  be  sufficiently  stiff 
for  the  work.  There  shall  be  a  metal  plug  in  the  bottom  of  the 
.strainer  completely  excluding  all  sand.  The  strainer  shall  be  at- 
tached to  the  casing  by  a  water-tight  joint. 

"The  lateral  pipes  leading  from  any  well  to  the  conduit  shall 
be  of  cast  iron  with  hub  and  spigot  joints.  The  size  of  the  pipe 
shall  depend  upon  the  flow  of  the  well  which  it  connects  with  the 
conduit  and  upon  the  distance  from  the  well  to  the  conduit,  and 
as  may  be  ordered  by  the  engineer. 

"The  main  conduit  pipe  shall  be  of  cast  iron  with  hub  and 
spigot  joints  36  in.  inside  diameter,  laid  on  a  level. 

"The  entire  system  of  conduit  and  lateral  pipes  shall  be  tested 
when  completed  to  a  hydrostatic  pressure  of  100  pounds  per 
square  inch  and  the  pressure  maintained  there  until  there  is  satis- 
factory evidence  of  tight  joints.  The  contractor  shall  frunish 
pumps,  tools  and  all  facilities  for  this  test. 

"All  material  and  workmanship  shall  be  guaranteed  for  a 
period  of  six  months  from  the  completion  of  the  work,  and  the 
pipe  lines  shall,  during  that  period,  be  maintained  by  the  con- 
tractor in  a  perfect  and  water-tight  condition  and  the  wells  be 
flowing  freely.  There  must  be  no  evidence  of  sand  accumulating 
in  the  wells  as  a  direct  result  of  imperfect  joints  and  an  imperfect 
plugging  of  the  bottom  of  the  strainer/' 

It  will  be  seen  from  these  specifications,  that  the  conditions 
laid  down  for  the  contractor  at  the  outset  of  such  a  piece  of  work 
cannot  be  very  definite.  The  Galveston  wells  were  of  the  sim- 
plest type  and  required  no  rock  drilling,  yet  the  specifications 
could  give  absolutely  definite  information  on  very  few  points. 
Specifications  for  wells  in  rock  would  necessarily  be  different  from 
those  quoted,  but  it  will  probably  be  found  best  in  draughting 
them  to  avoid  giving  any  particulars  which  are  not  absolutely 
certain,  and  refer  the  contractor  to  the  engineer  for  directions  as 
the  work  progresses.  Many  of  the  minor  features  of  a  deep  well 
plant  cannot  be  definitely  determined  until  the  wells  are  sunk 
and  tested,  and  to  give  unmatured  details  in  the  original  speci- 
fications will  furnish  the  contractor  a  hook  on  which  to  hang 
troublesome  claims  for  extras,  a  source  of  annoyance  and  often  of 
bad  feeling. 


WATER-WORKS    MANUAL.  131 

Wells  are  now  cased  to  their  full  depth,  with  few  exceptions. 
Sometimes  the  casing  is  in  several  sizes,  so  that  the  well  resembles 
a  drawn-out  telescope;  if  this  plan  is  adopted  the  connection  be- 
tween pipes  of  different  diameters  must  be  water-tight.  More  fre- 
quently, however,  the  pipe  remains  the  same  diameter  from  top 
to  bottom.  Which  plan  will  ultimately  prove  the  more  satisfac- 
tory cannot  always  be  foretold,  as  conditions  may  render  imprac- 
ticable the  sinking  of  a  pipe  of  uniform  diameter. 

When  the  casing  is  not  carried  down  into  the  stratum  it  is  de- 
sired to  tap,  the  water  may  be  contaminated  by  that  from  higher 
strata.  In  this  case  the  pure  water  must  be  drawn  off  through  a 
small  tube  sunk  for  the  special  purpose,  which  is  provided  with  a 
packing  on  the  outside  for  hermetically  sealing  the  good  water 
from  that  above.  A  number  of  devices  employing  rubber  rings  or 
helices  are  made  for  the  purpose,  while  if  none  of  them  is  at  hand 
a  seed  bag  will  probably  answer.  To  make  such  a  bag,  an  open 
cylinder  or  bag  of  stout  leather  is  slipped  over  the  inner  or  dis- 
charge pipe,  and  tied  firmly  at  the  bottom.  The  space  between 
the  bag  and  the  pipe  is  then  filled  with  dry  flaxseed  and  the  upper 
end  of  the  bag  lashed  firmly  to  the  pipe.  This  bag  is  lowered 
until  it  reaches  the  proper  depth  to  intercept  the  flow  of  unde- 
sirable water  toward  the  bottom  stratum,  and  held  there  until  the 
water  has  caused  the  seed  to  swell  and  fill  tightly  the  space  be- 
tween the  bore-hole  and  the  discharge  pipe. 

YIELD   OF   WELLS. 

The  development  of  deep  well  supplies,  either  artesian  or  non- 
flowing,  is  a  matter  requiring  careful  study,  for  the  subject  is  by 
no  means  as  simple  as  it  seems.  The  elements  of  the  problem  are 
all  that  can  be  discussed  in  these  articles.  In  the  first  place,  it  is 
necessary  to  refer  again  to  the  geological  reason  for  wells,  shown 
diagrammatically  in  Figure  27.  The  well  in  this  figure  is  fed  by 
the  rainfall  on  an  outcrop  of  porous  material  much  higher  than 
the  surface  of  the  ground  where  the  well  is  sunk.  The  conse- 
quence is  that  the  frictional  resistance  to  the  passage  of  the  water 
through  the  stratum  is  less  than  the  difference  in  elevation  be- 
tween the  outcrop  and  the  valley,  and  the  well  is  of  the  flowing 
type.  Suppose  it  is  prolonged  upward  by  a  series  of  pipes,  as  was 
done  in  some  interesting  experiments  by  Mr.  T.  T.  Johnson  at 
Savannah,  until  the  elevation  is  reached  at  which  no  water  is 
discharged.  This  is  marked  0  in  the  diagram.  Now  let  these 


132 


WATER-WORKS    MANUAL. 


pipes  be  dropped  25  and  50  feet  respectively,  and  the  discharge 
measured  at  each  elevation.  These  discharges  will  be,  say,  50,000 
and  100,000  gallons  in  24  hours,  as  marked  on  the  diagram.  The 
reason  for  these  different  rates  of  discharge  is  manifestly  that  the 
head  between  the  catchment  area  where  the  rainfall  is  collected 
and  the  elevation  at  which  the  well  discharges  has  been  varied, 
the  greater  the  head  the  greater  being  the  discharge.  The  fric- 
tional  resistance  is  practically,  although  not  exactly,  the  same 
whether  the  discharge  is  at  the  0,  25  or  50  elevation. 

Continuing  the  experiment  by  measuring  the  flow  when  the 
well  is  stopped  below  the  surface  of  the  ground  at  elevation  75,  so 
that  the  water  does  not  have  to  rise  above  that  elevation,  let  it  be 
assumed  that  the  measured  discharge  is  150,000  gallons  per  day. 
It  will  be  noticed  that  if  the  discharges  at  the  various  elevations 
are  represented  by  the  lengths  of  horizontal  lines,  as  shown  in  the 


FIGURE  27.— YIELD  OF  WELLS. 

illustration,  the  line  connecting  the  extremities  of  these  hori- 
zontal lines  is  straight.  While  this  is  a  theoretical  case,  it  is  for- 
tunately true  that  these  discharge  curves,  as  they  are  called,  are 
usually  found  by  actual  experiment  to  be  practically  straight 
lines. 

In  case  a  well  has  been  driven,  the  discharge  should  be  meas- 
ured when  the  outlet  is  at  several  different  elevations.  This  is  an 
easy  matter  when  the  well  is  artesian,  but  somewhat  more  difficult 
when  it  is  non-flowing.  In  the  latter  case,  the  discharge  at  vari- 
ous depths  below  the  surface  may  be  found  by  using  horizontal 
plunger  pumps  and  varying  the  suction  lift  from  time  to  time. 
That  is  to  say,  the  pump  can  be  run  at  first  with  a  suction  lift  of 
5  feet.  After  measuring  this  discharge  with  some  care,  the  pump 
can  be  speeded  until  the  suction  lift  is  10  feet,  and  the  process 


WATER-WORKS    MANUAL.  133 

continued  until  the  lift  is  25  feet.  Such  a  procedure,  which  is 
equivalent  to  cutting  off  the  well  at  these  different  depths,  so  as 
to  let  it  discharge  freely,  will  enable  the  discharge  curve  to  be 
drawn  with  sufficient  accuracy  for  all  practical  purposes.  It  may 
happen,  of  course,  that  the  water  will  not  rise  in  the  well  high 
enough  for  a  pump  on  the  surface  to  operate  properly.  In  this 
case,  some  of  the  various  pumping  apparatus  referred  to  in  the 
chapter  on  pumping  will  be  necessary,  the  air  lift  being  particu- 
larly useful  on  account  of  the  small  obstruction  it  offers  to  the 
discharge  of  the  well. 

In  studying  these  discharge  curves  it  is  necessary  to  bear  in 
mind  that  while  the  yield  of  a  well  increases  uniformly  as  the 
point  of  delivery  is  lowered,  a  depth  may  be  reached  at  which  the 
quantity  drawn  off  is  greater  than  the  supply.  Hence  such  a 
heavy  draught  will  gradually  diminish  the  supply,  and  to  avoid 
any  such  occurrence  after  works  have  been  built,  the  wells  have 
sometimes  been  pumped  at  the  maximum  delivery  desired  for  a 
period  of  several  weeks  or  months  before  going  ahead  with  the 
construction  of  the  plant. 

The  great  advantage  of  knowing  the  discharge  curve  of  a  well 
is  the  fact  that  it  enables  the  engineer  to  select  his  pumping  ap- 
paratus intelligently.  He  may  find  it  desirable,  as  at  Memphis, 
Tenn.,  and  Riverside,  111.,  to  place  a  horizontal  plunger  pump 
many  feet  below  the  surface,  or  the  diagram  may  be  such  as  to 
convince  him  that  similar  pumps  on  or  slightly  below  the  surface 
will  furnish  an  ample  amount  of  water.  The  choice  between  deep 
well  pumps  and  air  lifts  may  also  be  aided  to  a  certain  extent  by 
the  character  of  the  discharge  curve. 

In  testing  the  capacity  of  any  well  care  should  be  taken  that 
none  of  the  water  escapes  into  overlying  strata  before  reaching 
the  surface,  or  that  the  volume  drawn  from  the  well  does  not  in- 
clude impure  water  from  strata  which  must  be  subsequently  shut 
off.  A  possible  case  also  is  that  of  a  bore  hole  which  has  been 
sunk  through  several  strata  bearing  good  water  in  the  vain  hope 
of  finding  larger  volumes  lower.  In  case  the  whole  is  not  plugged 
just  below  the  lowest  water  bearing  stratum  it  will  afford  a  path 
for  serious  waste  in  case  any  of  the  lower,  dry  strata  are  perme- 
able. 

The  history  of  the  development  of  the  water  supply  at  Rock- 
ford,  111.,  affords  a  good  example  of  the  possibilities  of  deep  wells. 


134  WATER-WORKS    MANUAL. 

Under  that  city  are  the  two  well-known  sandstone  formations 
from  which  many  supplies  in  Illinois  and  Wisconsin  are  drawn. 
The  lowest  formation  is  the  Potsdam.  Above  that  is  a  stratum  of 
impervious  magnesian  limestone  a  little  over  100  feet  thick,  and 
then  comes  the  water-bearing  St.  Peter  sandstone,  about  200  feet 
thick.  This  in  turn  is  covered  with  glacial  drift.  The  first  deep 
well  supply  was  from  five  8-inch  wells  sunk  from  1,300  to  2,000 
feet  to  the  Potsdam  sandstone.  After  a  short  time  the  yield  of 
these  wells  proved  insufficient,  and  others  were  sunk  into  the  St. 
Peter  sandstone.  Even  these  proved  unable  to  supply  the  de- 
mand, and  an  air  lift  system  was  introduced,  as  described  in  "The 
Engineering  Record."  This  furnished  the  needed  increase  in  the 
volume  of  water,  but  it  required  too  much  coal  to  be  satisfactory 
to  the  authorities.  So  a  careful  study  of  the  wells  was  made  in 
much  the  manner  just  outlined.  The  air  lift  was  used  to  deter- 
mine the  discharge,  the  elevation  of  the  water  in  the  wells  being 
determined  by  a  float  attached  to  a  steel  tape.  It  was  finally  de- 
cided that  the  best  way  of  securing  the  desired  quantity  of  water 
was  to  sink  a  shaft  and  connect  it  with  the  wells  by  tunnels. 
Three  centrifugal  pumps  have  been  placed  in  alcoves  at  the  bot- 
tom of  the  shaft,  and  are  driven  by  rope  transmission  from  the 
three  independent  vertical  engines  at  the  surface.  Each  pump  ia 
of  3,000,000  gallons  capacity. 

Before  closing  this  necessarily  brief  discussion  of  deep  wells, 
the  writer  feels  compelled  to  point  out  again  that  the  develop- 
ment of  a  supply  from  a  source  several  hundred  feet  below  the 
surface  is  naturally  somewhat  of  a  lottery.  This  is  shown  by  the 
experience  in  many  places,  although  but  one  instance  can  be  cited 
here,  that  of  Chester,  S.  C.  The  city  first  engaged  a  geologist  to 
examine  the  locality;  after  two  days'  study  he  selected  three 
points  where  artesian  water  would  probably  be  found  at  a  depth 
of  400  to  500  feet.  Mr.  Perry  Andrews,  of  Elmira,  N.  Y.,  was 
engaged  to  sink  the  well.  He  began  boring  in  a  hollow  near  a 
stream,  and  at  the  end  of  five  or  six  months  had  sunk  a  bore  hole 
about  500  feet  into  the  rock.  A  supply  of  30,000  gallons  a  day 
was  obtained,  but,  on  Mr.  Andrews'  advice,  the  site  was  aban- 
doned and  work  begun  a  mile  away  on  a  hill  side.  This  attempt 
was  successful,  for  a  supply  of  about  250,000  gallons  was  obtained 
by  sinking  a  well  400  feet  deep. 


WATER-WORKS    MANUAL.  135 

QUALITY  OF  GROUND  WATER. 

A  few  words  should  be  added  at  this  place  concerning  the  qual- 
ity of  well  waters.  Where  the  wells  are  shallow  they  are  exposed 
to  contamination  from  the  surface,  and,  as  a  matter  of  fact,  shal- 
low wells  in  the  vicinity  of  dwellings  are  always  regarded  with 
suspicion  by  sanitarians.  In  the  interpretation  of  an  analysis 
of  water  from  such  a  source  it  must  be  remembered,  however,  that 
the  soil  about  a  well  may  contain  a  certain  amount  of  harmless 
organic  matter  which  will  cause  the  amount  of  nitrates  in  the 
water  to  be  unusually  high.  In  the  preliminary  work  connected 
with  a  chemical  survey  of  the  shallow  well  waters  in  Illinois, 
Prof.  A.  W.  Palmer  adopted  the  following  maximum  limits  of 
impurities,  in  parts  per  million,  for  supplies  which  may  be  used 
with  safety:  Total  solids,  500;  oxygen  consumed,  2;  chlorine,  15; 
nitrogen  as  free  ammonia,  0.02;  nitrogen  as  albuminoid  ammonia, 
0.05;  nitrogen  as  nitrites,  0.001;  nitrogen  as  nitrates,  15.  The 
limit  for  nitrates  seems  very  high  if  judged  by  the  limits  of  0.5 
part  in  Maryland,  1  part  in  Iowa,  or  0.9  part  in  Michigan,  but 
"the  fertile  drift  soils  of  Illinois  are  naturally  highly  nitrogenous, 
and  it  is  probable  that  for  this  region  the  quantities  of  nitrates 
normally  contained  in  unpolluted  ground  waters  may  range  much 
higher  than  elsewhere."  Even  when  Prof.  Palmer  applied  the 
liberal  limits  mentioned,  he  found  but  few  instances  of  shallow 
wells  which  could  be  used  safely.  In  Massachusetts,  the  unpol- 
luted ground  water  from  near  the  surface  is  stated  to  differ  from 
the  unpolluted  surface  water  in  having  only  about  one-tenth  as 
much  free  and  albuminoid  ammonia  with  five  times  as  much  ni- 
trogen as  nitrates.  These  few  observations  will  show  how  unde- 
sirable it  is  for  any  one  not  an  experienced  chemist  to  attempt  to 
interpret  the  results  of  an  analysis,  and  also  how  important  it  is 
that  all  the  available  information  concerning  the  surroundings  of 
wells  and  the  strata  they  penetrate  should  be  sent  to  a  chemist  re- 
tained to  pass  upon  the  potability  of  any  supply. 

As  regards  the  Illinois  wells,  Prof.  Palmer  has  made  some  in- 
teresting comments  in  his  preliminary  report,  which  are  repro- 
duced here  on  account  of  their  somewhat  general  application: 

"The  waters  from  shallow  wells  are  well  aerated,  and  are  clear, 
sparkling,  cool,  and  of  agreeable  taste;  those  from  the  deeper 
(drift)  wells,  on  the  other  hand,  contain  little  or  no  oxygen,  pos- 
sess in  many  cases  a  disagreeable  taste  due  to  the  presence  of 


136  WATER-WORKS    MANUAL. 

marsh  gas,  accompanied  occasionally  by  minute  quantities  of  sul- 
phuretted hydrogen,  and  are  either  turbid  or  become  turbid 
quickly  on  exposure  to  air,  owing  to  the  oxidation  of  the  iron 
carbonate  which  they  contain  and  the  consequent  precipitation  of 
the  insoluble  ferric  compounds.  The  precipitating  particles  are 
often  so  minute  as  to  be  at  first  indistinguishable  except  from  the 
color  they  impart  to  the  water,  but  after  a  short  exposure  to  the 
air  the  water  becomes  opalescent,  then  decidedly  turbid;  finally  a 
brown  deposit  similar  to  iron  rust  is  produced,  and  after  this  has 
separated  the  water  becomes  clear  and  colorless. 

"Although  these  unpleasant  characteristics  of  the  deep  drift 
waters  give  rise  to  much  prejudice  and  objection  to  their  general 
use  for  drinking,  nevertheless,  from  the  sanitary  standpoint,  they 
are  usually  to  be  preferred  to  the  clear  and  palatable  waters  of  the 
shallow  wells,  since  the  evidence  of  numerous  analyses  shows  that 
they  are  far  less  subject  to  pollution  with  refuse  animal  matters 
than  are  the  latter,  while  the  organic  matters  which  they  contain 
are  derived  from  the  buried  vegetable  remains  referred  to  above, 
and  are  comparatively  harmless." 

One  source  of  dissatisfaction  with  certain  ground-water  sup- 
plies from  wells  or  filter  galleries  near  natural  bodies  of  water  is 
caused  by  the  organism  Crenothrix.  These  supplies  are  obtained 
by  imperfect  filtration  from  the  neighboring  stream  or  pond,  and 
contain  an  unusual  amount  of  free  ammonia  and  some  protoxide 
of  iron.  The  bacterium  has  the  peculiar  property  of  separating 
the  dissolved  iron  from  water  and  incorporating  it  in  its  sheath, 
where  it  exists  as  iron  rust.  Such  waters  are  unsatisfactory  for 
use  in  the  laundry,  because  white  clothes  become  much  discolored 
by  the  rust,  and  some  supplies  have  been  abandoned  entirely  on 
account  of  the  trouble  caused  by  this  organism. 

The  most  common  objection  to  deep-well  waters  is  their  hard- 
ness, although  many  of  them  do  not  have  this  drawback.  A  valu- 
able monograph  on  the  subject,  written  by  Mrs.  Ellen  H.  Rich- 
ards, was  published  in  the  twenty-seventh  annual  report  of  the 
Massachusetts  State  Board  of  Health.  As  that  article  may  be 
too  technical  in  its  chemical  portions  for  general  readers,  the  fol- 
lowing discussion  of  the  subject  is  reprinted  from  a  report  on  the 
water  supply  of  Winnipeg,  by  Mr.  Rudolph  Hering,  M.  Am.  Soc. 
C.  E.: 

There  are  two  kinds  of  hardness:  Temporary  and  permanent. 


WATER-WORKS    MANUAL,  137 

The  former  is  usuclly  caused  by  the  carbonates  and  the  latter  by 
the  sulphates  of  lime  or  magnesia. 

Temporary  hardness  can  be  removed: 

First. — By  a  sufficient  quantity  of  soap. 

Second. — By  carbonate  of  soda  (washing  soda).  The  carbonate 
of  soda  unites  with  the  bicarbonate  of  lime  dissolved  in  the  water, 
resulting  in  the  formation  of  bicarbonate  of  soda  and  carbonate 
of  lime.  The  former  remains  in  solution  and  does  not  harden  the 
water;  the  latter  is  precipitated  as  a  fine,  white  powder. 

Third. — By  boiling.  The  bicarbonate  of  lime  is  decomposed 
by  heat  into  carbonic  acid,  which  escapes,  and  carbonate  of  lime, 
which  is  precipitated  as  a  fine,  white  powder. 

Fourth. — By  a  solution  of  freshly  burnt  lime,  or  lime-water. 
The  carbonates  of  lime  and  magnesia  are  changed  into  mono- 
carbonates  by  the'  hydrate  of  lime  uniting  with  the  extra  carbonic 
acid,  which  is  either  free  or  combined  as  bicarbonate  in  the  hard 
water.  The  resulting  insoluble  mono-carbonates  deposit  as  a  fine 
powder.  Carbonate  of  lime  is  not  entirely  insoluble  in  water,  and 
a  small  portion  always  remains  in  it.  The  soluble  bicarbonates  of 
lime  or  magnesia,  having  thus  lost  half  their  carbonic  acid,  are 
reduced  to  the  same  insoluble  mono-carbonates  and  are  also  pre- 
cipitated. This  process,  being  the  least  expensive,  is  the  one  here 
rcommended. 

Permanent  hardness  can  be  removed: 

First. — By  a  sufficient  quantity  of  soap,  as  before. 

Second. — By  carbonate  of  soda.  The  soda  in  this  case  unites 
with  the  sulphate  of  lime  or  magnesia  dissolved  in  the  water,  re- 
sulting in  the  formation  of  the  neutral  and  inert  sulphate  of  soda, 
and  the  insoluble  carbonate  of  lime  or  magnesia.  The  former 
remains  in  solution  and  does  not  harden  the  water;  the  latter  is 
precipitated  as  a  fine  white  powder.  In  cool  water  the  presence 
of  free  carbonic  acid,  or  of  bicarbonates,  interferes  somewhat  with 
this  reaction;  but  the  combined  lime-and-soda  process  obviates 
this  difficulty  to  a  large  extent.  As  permanent  hardness  is  usual- 
ly present  with  temporary  hardness,  the  lime  and  soda  can  be 
mixed  and  together  added  to  the  water. 

To  remove  permanent  hardness  this  process  is  the  least  expen- 
sive one  for  city  supplies. 


CHAPTER  XII.— PUMPS, 

The  pumping  plant  used  in  works  of  the  size  considered  in  this 
series  of  articles  may  be  roughly  divided  into  two  classes,  well  and 
low-lift  plants.  Under  the  first  head  is  included  the  apparatus 
used  to  raise  water  from  wells  in  which  the  power  or  driving 
machinery  cannot  be  placed.  It  includes  deep  well  pumps,  air 
lifts  and  a  number  of  special  appliances,  which  have 
been  used  in  a  few  instances.  Under  the  second  head 
are  included  the  plants  which  are  placed  wholly  on  or  near  the 
surface.  This  is  merely  an  arbitrary  classification  to  simplify  the 
arrangement  of  the  information  on  the  subject  presented  in  this 
chapter  and  the  next,  which  are  intended  solely  to  assist  water- 
works committees  and  others,  not  acquainted  with  engineering 
work,  in  selecting  pumping  machinery. 

The  pumps  used  on  or  near  the  surface  may  be  employed  to 
force  water  into  a  reservoir  of  some  sort,  which  keeps  the  head 
constant  against  which  they  work, .  or  the  machinery  may  force 
water  directly  into  the  pipes  and  be  designed  to  furnish  higher 
pressures  than  usual  when  fires  or  other  emergencies  occur.  The 
latter  system  of  operation  was  formerly  known  as  the  Holly,  but 
is  generally  spoken  of  to-day  as  direct  pumping. 

Pumping  machinery  is  also  classified  according  to  the  method 
by  which  it  is  driven,  whether  by  a  direct  connected  steam  end  or 
by  power  furnished  in  some  other  manner.  The  greatest  propor- 
tion of  the  pumping  plants  in  this  country  are  operated  by  steam, 
and  it  is  therefore  natural  to  turn  to  them  first;  it  is  well  to  re- 
member, however,  that  gasoline  engines  and  electric  motors  have 
only  recently  come  into  favor  for  driving  pumps,  and  on  account 
of  their  advent  the  next  ten  years  are  probably  destined  to  see  a 
considerable  change  in  small  pumping  plants. 

The  best  method  for  any  one  interested  in  the  purchase  of 
pumping  machinery,  but  uninformed  as  to  its  general  construc- 
tion, to  obtain  a  general  knowledge  of  the  subject  is  to  secure  the 


WATER-WORKS    MANUAL.  139 

catalogues  of  the  manufacturers  whose  cards  appear  in  "The 
Engineering  Record."  These  firms  have  invested  a  large  capital 
in  their  plants  and  have  taken  advantage  of  every  improvement 
that  specially  trained  mechanical  experts  and  ample  financial  re- 
sources could  find.  American  pumping  machinery  is  to-day  so 
admirable  that  hydraulic  engineers  very  rarely  make  any  plans 
for  this  portion  of  a  water  system,  and  content  themselves  with 
specifying  the  results  they  wish.  Hence,  no  attempt  will  be  made 
to  explain  more  of  the  design  and  construction  of  pumps  than  is 
necessary  to  point  out  in  a  very  general  way  the  conditions  for 
which  each  class  is  best  adapted. 

The  larger  part  of  the  steam,  pumps  in  use  in  American  water- 
works are  of  the  direct-acting  type,  in  which  the  piston  rod  of  the 
steam  cylinder  is  prolonged  to  form  the  rod  of  the  piston  or 
plunger  in  the  corresponding  water  cylinder.  Such  a  pump  can 
be  built  for  less  money  than  a  crank-pump  .of  the  same  capacity. 
It  occupies  less  space  and  weighs  less.  On  the  other  hand,  it  is 
more  wasteful  of  steam  than  the  crank  and  fly  wheel  .pumps,  unless 
fitted  with  special  devices  raising  its  price. 

The  simplest  pumps  are,  of  course,  those  with  a  single  steam 
cylinder  and  a  single  water  cylinder.  Horizontal  pumps  of  thi.-3. 
type  are  sometimes  used  in  water-works,  mainly  for  feeding  boil- 
ers and  such  purposes  and  in  raising  water  from  deep  wells.  The 
steam  cylinder  of  well  pumps  is  usually  mounted  on  a  standard 
which  can  be  placed  over  the  well  hole,  and  the  piston  rod  is 
continued  downward  by  wooden  bars  to  the  plunger.  Steam  is 
admitted  during  the  whole  stroke  and  the  breakage  of  the  pump 
rods  or  the  failure  of  the  water  supply  is  liable  to  wreck  the 
cylinder,  the  piston  offering  no  resistance  under  these  conditions 
to  the  force  of  the  steam.  To  provide  against  such  an  accident, 
it  is  usual  to  furnish  the  pumps  with  adjustable  valves,  which 
check  the  escape  of  the  exhaust  steam.  These  allow  the  exhaust 
to  pass  off  with  sufficient  rapidity  to  produce  little  effect  on  the 
working  of  the  engine,  but  in  case  the  rod  breaks  or  the  water 
fails,  allowing  the  piston  to  jump  ahead  violently,  the  exhaust  is 
compressed  into  a  cushion  which  checks  the  blow  of  the  piston. 
Special  arrangements  are  also  provided  for  varying  the  amount 
of  steam  supplied  to  each  end  of  the  cylinders.  The  water  end  of 
these  pumps  will  be  referred  to  later.  Some  manufacturers  sup- 
ply a  horizontal  steam  cylinder  for  well  pumps,  which  is  fur- 


140  WATER-WORKS    MANUAL. 

n  i  shed  with  a  heavy  working  beam,  like  a  large  bell  crank  lever. 
One  arm  is  pinned  to  a  connecting  rod  running  from  the  piston 
of  the  engine  and  the  other  is  attached  to  the  pump  rods.  Such 
an  arrangement  is  preferred  abroad  to  the  vertical  type  usually 
installed  in  the  United  States,  as  it  is  unnecessary  to  move  the 
steam  cylinder  or  disconnect  any  of  the  steam  or  exhaust  piping 
in  order  to  reach  the  working  parts  in  the  well. 

STEAM   CONSUMPTION. 

Except  where  deep  wells  are  the  source  of  supply,  steam  pumps 
are  rarely  used  for  wrater-works  purposes  without  some  attempt  is 
made  to  use  the  steam  expansively,  and  thus  gain  more  work  from 
it  than  is  possible  when  full  boiler  pressure  is  exerted  on  the 
piston  during  its  entire  stroke.  This  advantage  is  secured  by 
means  of  a  second  or  low-pressure  cylinder,  placed  in  a  line  with 
the  first  or  high-pressure  cylinder,  the  pump  plunger  and  the  pis  - 
tons  in  both  steam  cylinders  being  connected  by  one  piston  rod. 
The  exhaust  steam  from  the  high-pressure  cylinder  passes  to  the 
low  pressure  cylinder  and  expands  behind  its  piston,  thus  doing 
much  useful  work  which  is  lost  unless  this  expansion  takes  place. 
Owing  to  the  peculiar  features  of  direct-acting  pumping  ma- 
chinery, it  is  impracticable  to  use  steam  expansively  in  a  single 
cylinder  steam  end,  in  the  manner  followed  in  a  flywheel  engine 
having  but  one  cylinder,  and  it  is  necessary  to  use  a  compound 
steam  end  to  secure  this  advantage.  In  other  words  a  compound 
steam  pump  is  necessary  to  obtain  the  effect  produced  by  a  cut-off 
device  on  an  ordinary  engine  for  power  purposes  or  on  a  crank 
and  flywheel  pump;  it  will  save  from  20  to  30  per  cent,  of  the 
steam  required  to  do  the  same  work  in  a  non-compound  pump. 

Still  greater  economy  can  be  obtained  by  condensing  the  steam 
exhausted  from  the  low-pressure  cylinder,  so  that  the  motion  of 
the  piston  is  due  to  steam  pressure  on  one  face  and  a  partial 
vacuum,  due  to  the  condensing  apparatus,  on  the  other  face.  The 
condensation  is  usually  effected  by  playing  fine  jets  of  water 
through  the  exhaust  steam  and  then  pumping  by  an  air  pump 
the  condensation  and  any  air  that  may  find  its  way  into  the  con- 
denser into  the  boilers  or  an  adjoining  waterway,  according  as 
the  water  is  to  be  used  over  again  or  thrown  away.  The  use  of 
this  condensing  apparatus  requires  considerable  water,  but  it 
saves  about  20  per  cent,  of  the  steam  needed  when  it  is  not  used. 
In  some  localities  there  may  be  plenty  of  water  available,  but  not 


WATER-WORKS    MANUAL.  141 

of  a  quality  fit  for  boiler  purposes;  in  this  case  a  surface  condenser 
may  be  used,  which  will  return  to  the  boilers  all  but  about  5  per 
cent,  of  the  water  originally  evaporated  by  them,  the  condensa- 
tion being  produced  by  the  inferior  but  cheap  supply.  Some- 
times the  condenser  is  placed  in  the  main  suction  or  discharge 
pipe,  where  the  condensation  is  effected  by  the  water  passing 
through  the  main  pump.  The  air  pump  in  both  jet  and  surface 
condensers  is  sometimes  driven  by  the  main  engine  and  is  some- 
times independent. 

It  should  be  mentioned  here  that  it  is  customary  to  provide  the 
compound  pumps  employed  in  direct-pumping  water-works  with 
special  valves  whereby  steam  at  boiler  pressure  can  be  admitted  to 
the  low-pressure  cylinders.  In  case  of  fire  these  valves  are  opened 
and  the  water  pressure  in  the  street  mains  raised  considerably  by 
the  increased  power  obtained  in  this  way. 

Even  the  best  of  these  compound  pumps  of  the  direct-acting 
type  fail  to  use  steam  as  economically  as  the  crank  and  flywheel 
engines,  and  inventors  worked  for  a  number  of  years  to  provide 
an  attachment  which  would  remedy  this  disadvantage.  Several 
arrangements  have  been  designed  and  a  number  of  them  are  in 
use.  They  are  mechanical  contrivances  of  much  ingenuity,  and 
fulfill  their  purpose  satisfactorily.  They  are  called  high-duty 
attachments. 

Another  method  of  increasing  the  economy  of  a  compound  con- 
densing pump  is  to  add  a  third  steam  cylinder.  In  such  a  steam 
end  the  exhaust  from  the  high-pressure  cylinder  is  taken  to  the 
second  or  intermediate  cylinder,  and  there  made  to  do  work  while 
expanding,  and  is  then  taken  to  the  low-pressure  cylinder  and 
made  to  furnish  still  more  work  by  further  expansion.  Such  a 
steam  end  is  in  most  cases  provided  with  condensing  apparatus, 
and  if  it  is  also  furnished  with  a  high  duty  attachment,  the  pump- 
ing engine  represents  the  most  economical  form  of  the  direct- 
acting  type  now  built. 

A  large  proportion  of  the  direct-acting  engines  now  in  use  are 
of  the  duplex  type,  that  is  to  say,  they  consist  of  two  complete 
pumping  engines  placed  side  by  side,  and  so  connected  that  the 
steam  valves  are  actuated,  not  by  the  engine  they  control,  but  by 
its  mate.  The  effect  of  such  a  device,  according  to  Mr.  William 
M.  Barr's  book  entitled  "Pumping  Machinery,"  "is  to  allow  one 
piston  to  proceed  to  the  end  of  the  stroke,  and  gradually  come  to  a 


142  WATER-WORKS    MANUAL. 

state  of  rest;  during  the  latter  part  of  this  movement  the  opposite 
piston  then  moves  forward  in  its  stroke,  and  also  gradually  comes 
to  a  state  of  rest;  but  in  its  movement  forward,  and  before  reach- 
ing the  end  of  its  stroke,  the  slide  valve  controlling  the  first  pis- 
ton is  reversed,  and  in  consequence  the  first  piston  returns  to  its 
original  position,  and  in  nearing  the  end  of  its  stroke,  it  reverses 
in  a  similar  manner  the  slide-valve  controlling  the  second  piston; 
these  movements  are  both  uniform  and  continuous  so  long  as 
steam  is  supplied  to  the  piston." 

The  same  author  sums  up  the  advantages  of  the  duplex  type  as 
follows:  "The  very  great  success  attending  the  introduction  of  the 
duplex  pumping  engine  shows  that  it  well  provides  the  means  of 
pumping  heavy  columns  of  water  with  ease  and  safety  to  tho 
machinery  employed,  permitting  the  application  of  any  amount 
of  power  required  to  lift  the  water  column  without  violent  or 
abrupt  action  upon  the  water,  thus  meeting  an  acknowledged  de- 
mand that  the  rate  of  movement  of  the  water  column  through  the 
forcing  main  shall  be  as  nearly  as  possible  uniform,  so  that  no 
considerable  alteration  of  pressure  shall  be  shown  at  any  time 
while  the  pump  is  working.  It  also  meets  the  requirement  that 
the  propulsion  of  the  water  shall  be  produced  by  the  the  use  of 
the  smallest  practicable  amount  of  moving  material  for  transmit- 
ting the  force  of  the  steam  to  the  column  of  water,  in  order  to  re- 
duce to  the  lowest  point  the  momentum  of  moving  parts,  and  the 
hurtful  effects  due  thereto  in  case  of  derangement  of  the  valves 
or  pipes.  The  time  allowed  at  the  end  of  each  stroke  before  the 
piston  takes  up  its  return  motion  is  sufficient  to  permit  the  water 
valves  to  seat  quietly,  and  to  allow  the  incoming  supply  to  com- 
pletely fill  the  water  cylinder." 

Crank  and  flywheel  pumps  differ  from  the  direct-acting  type  in 
one  feature,  the  result  of  their  construction,  which  influences  at 
times  the  design  of  the  adjuncts  to  the  force  main.  In  direct- 
acting  pumps  the  steam  and  water  pistons  move  with  practically 
the  same  velocity  throughout  each  stroke,  with  the  result  that 
water  passes  through  the  pumps  at  a  fairly  uniform  velocity. 
With  crank  pumps  this  is  not  true;  the  flywheel  of  such  pumps 
revolves  at  a  uniform  rate,  but  this  uniformity  is  maintained  only 
by  a  variation  in  the  speed  of  the  steam  pistons  and  hence  of  the 
water  pistons.  An  important  point  about  such  pumps  is  the  fact 
that  the  length  of  the  stroke  is  definitely  fixed;  on  this  account 


WATER-WORKS   MANUAL.  143 

care  must  be  taken  with  the  steam  piping  to  prevent  any  water 
entering  in  the  cylinders.  If  this  occurs  something  is  apt  to 
break,  whereas  in  a  direct-acting  pump  with  its  variable  stroke, 
such  an  occurrence  is  not  so  liable  to  make  trouble,  and  less  pains 
need  be  taken  with  the  piping  in  consequence. 

The  advantages  of  the  type  under  consideration  are  stated  as 
follows  by  Mr.  H.  P.  M.  Birkinbine:  "A  higher  piston  speed  can 
be  had  with  a  crank  and  flywheel  pump  than  if  the  pump  were 
direct-acting,  for  the  reason  that  in  the  latter  type  the  termina- 
tion of  each  stroke  is  defined  and  secured  by  steam  acting  as  a 
cushion  to  counteract  the  force  of  the  moving  parts  and  of  the 
water.  In  large  steam  pumps  100  feet  per  minute  may  be  consid- 
ered as  the  limit  to  safe  piston  speed.  With  pumping  engines 
having  cranks,  connecting-rods  and  flywheels  to  terminate  and 
define  the  stroke  of  the  piston,  any  piston-speed  possible  to  the 
pumps  can  be  secured  with  safety.  The  power  stored  in  the  mov- 
ing mass  of  the  flywheel  at  the  termination  of  the  stroke,  is  car- 
ried to  the  beginning  of  the  next  stroke  without  any  loss  but  that 
due  to  the  friction  of  the  moving  parts  and  the  resistance  of  the 
air  to  the  motion  of  the  flywheel.  Then  the  practically  uniform 
speed  of  the  rim  of  the  flywheel  secures  the  desired  motion  for  the 
piston  through  the  connecting-rod  and  crank  of  the  pump  by 
gradually  retarding  the  motion  until  the  point  of  rest  is  reached, 
and  accelerating  it  after  the  piston  has  passed  that  point."  In 
brief,  it  may  be  said  that  the  advantages  of  the  crank  pump  are 
mainly  in  its  greater  economy  in  the  use  of  steam  and  its  higher 
piston  speed  as  compared  with  the  direct-acting  pump.  The  for- 
mer advantage  means  a  decrease  in  fuel  and  in  boiler  capacity, 
the  latter  a  greater  volume  of  water  delivered  from  water-ends  of 
the  same  size. 

Three  factors  should  be  considered  in  selecting  a  pumping  en- 
gine from  the  various  types  mentioned,  viz.:  first,  cost  of  engine 
and  boilers;  second,  cost  of  operation;  third,  cost  of  maintenance 
and  repairs,  including  the  loss  of  time  due  to  repairs.  The  second 
factor,  the  cost  of  operation,  is  influenced  considerably  by  'the 
length,  diameter  and  nature  of  the  force  main,  as  will  be  ex- 
plained later. 

A  moment's  reflection  will  show  that  the  first  cost  of  a  steam 
pump  will  depend  largely  on  the  steam  end  selected.  The  cheap- 
est type,  the  simple  non-condensing,  direct-acting  pump,  will  re- 


144  WATER-WORKS   MANUAL. 

quire  three  or  four  times  as  much  steam  and  coal  as  a  high  class 
compound  condensing  high-duty  pump  and  a  much  larger  boiler 
capacity,  for  it  cannot  use  steam  at  such  high  pressure  or  so  eco- 
nomically. Mr.  Charles  A.  Hague,  M.  Am.  Soc.  C.  E.,  recently 
printed  a  table  showing  the  effect  of  an  increase  in  initial  steam 
pressure  on  the  duty  which  it  is  possible  to  obtain  with  compound 
and  triple-expansion  steam  ends.  A  few  figures  from  this  table 
follow: 

Duty  per  1,000  Pounds  of  Steam. 
Steam 
Pressure.  Compound.  Triple-expansion. 

75 104,000,000   foot-pounds 

80 106,000,000 

85 107,000,000 

90... 108,000,000 

95 109,000,000 

100 110,000,000  125,000,000 

105 111,000,000  126,000,000 

110 112,000,000  126,000,000 

115 113,000,000  127,000,000 

120 ........114,000,000     '     128,000,000 

125 ...115,000,000     '     129,000,000 

129 130,000,000 

133..... 131,000,000 

137 132,000,000 

141. 134,000,000 

It  is  important  to  bear  in  mind  that  the  nature  of  the  service 
an  engine  is  called  upon  to  perform  makes  a  marked  difference  in 
the  relative  ultimate  economy  of  the  different  types.  A  pump 
becomes  more  expensive  as  its  type  is  raised,  and  in  some  in- 
stances the  money  saved  by  the  use  of  one  type  will  not  equal  its 
increased  cost  over  a  type  of  less  economy,  that  is,  one  using  more 
fuel  to  pump  the  same  quantity  of  water.  The  matter  of  load 
will  often  have  much  weight  in  the  choice  of  a  pump;  if  the  load 
is  that  due  to  a  reservoir  and  is  constant,  triple-expansion  will 
often  be  most  economical  where  much  water  has  to  be  handled, 
while  with  the  direct-pumping  system,  where  the  load  varies  be- 
tween night  and"  day  and  runs  up  quickly  during  fires,  a  com- 
pound steam  end  may  be  preferable. 

After  the  type  of  engine  has  been  chosen  it  is  an  easy  matter  to 
determine  whether  it  shall  be  vertical  or  horizontal.  If  the  sup- 
ply of  water  comes  from  a  river  subject  to  great  variations  in  its 
surface  level  or  from  wells  liable  to  become  seriously  taxed  during 
times  of  heavy  pumping,  the  pump  end  of  the  engine  should  be 
as  low  as  possible.  By  using  vertical  engines  this  can  be  accom- 


WATER-WORKS  MANUAL.  145 

plished  and  still  have  the  steam  ends  high  enough  to  be  readily 
accessible.  Another  advantage  of  the  vertical  engine  is  the  com- 
paratively small  floor  space  it  takes  up.  On  the  other  hand,  the 
horizontal  engine  in  the  smaller  sizes  costs  about  a  fifth  less,  it  is 
more  easily  examined  and  repaired,  and  requires  no  balancing  ap- 
paratus to  make  it  work  smoothly  on  light  loads. 

POWER  PUMPS. 

Not  many  years  ago  power  pumps  were  used  in  this  country  for 
water-works  purposes  only  in  connection  with  water-wheels. 
Plants  of  this  type  in  some  of  the  New  England  cities,  Phila- 
delphia, Richmond  and  a  few  other  places  were  often  described 
in  early  articles  on  water-works,  and  they  still  teach  valuable 
lessons.  But  power  pumping  to-day  is  in  a  very  different  condi- 
tion from  what  it  was  fifteen  years  ago,  and  no  one  interested  in 
small  water-works  can  afford  to  neglect  it.  The  independent 
water  end  driven  by  a  gas  or  gasoline  engine,  electric  motor  or 
yteam  engine  is  a  combination  which  offers  many  advantages  for 
small  plants.  It  has  already  been  mentioned  that  the  small  di- 
rect-acting steam  pump  is  decidedly  uneconomical  in  the  use  of 
steam.  In  Volume  xvii.  of  the  "Transactions"  of  the  American 
Society  of  Mechanical  Engineers  there  is  a  discussion  on  this  sub- 
ject from  which  a  few  statements  may  be  taken  with  advantage  to 
illustrate  this  lack  of  economy.  Dr.  Ghas.  E.  Emery  found  in  one 
large  establishment  many  pumps  using  as  much  as  240  pounds  of 
steam  per  net  horse  power  per  hour,  and  only  in  rare  cases  could 
one  be  found  which  was  furnishing  a  horse  power  for  each  80 
pounds  of  steam;  it  was  generally  believed  that  about  150  pounds 
per  horse  power  was  the  average  consumption.  These  small 
steam  pumps  were  replaced  by  power  pumps  operated  by  good 
high-pressure  non-condensing  engines.  Mr.  J.  G.  Wmship  stated 
that  a  large  saving  has  been  made  by  the  Tidewater  Oil  Company 
by  the  use. of  power  pumps  driven  by  an  automatic  cut-off  engine. 
But  passing  over  the  fact  that  small  pumps  do  not  use  steam 
economically,  power  pumps  offer  a  marked  advantage  in  not  ab- 
solutely requiring  a  steam  engine  and  its  attendant  boiler  plant 
and  coal  shed,  for  they  can  be  driven  equally  well  by  a  gas  or  gaso- 
line engine  or  an  electric  motor.  The  gas  engine  is  not  used  to 
any  considerable  extent  in  this  country,  but  it  has  been  so  em- 
ployed in  many  German  cities,  as  is  shown  in  an  illustrated  ar- 
ticle in  "The  Engineering  Record"  of  June  1,  1895. 


A46  WATER-WORKS    MANUAL. 

Gasoline  engines  offer  many  advantages  for  small  pumping 
plants,  because  of  the  ease  with  which  their  fuel  can  be  transport- 
ed, an  important  matter  where  the  pumping  station  must  be 
located  at  a  place  difficult  of  access,  and  because  they  require  little 
attendance  compared  with  a  steam  plant.  The  electric  motor  is 
as  easy  to  look  after,  and  where  it  is  used  there  is  no  need  what- 
ever of  transporting  fuel.  Hence  it  i's  not  surprising  that  such 
sources  of  power  are  causing  marked  changes  in  the  design  of 
small  pumping  stations.  Where  a  town  operates  a  small  electric 
lighting  plant,  and  finds  that  it  will  be  most  advantageous  to  lo- 
cate its  pumping  plant  some  distance  from  the  built-up  district, 
the  use  of  electric  motors  driving  power  pumps  should  certainly 
be  investigated.  The  lighting  plant  would  run  during  the  night 
and  the  pumping  plant  during  the  day,  thus  using  the  motor  part 
of  the  station  to  the  best  advantage  and  saving  part  of  the  ex- 
pense of  installation  and  operation  which  must  be  met  if  inde- 
pendent lighting  and  pumping  stations  were  constructed.  There 
are  good  reasons  for  the  belief  that  secondary  pumping  stations 
operated  by  electric  motors  will  also  be  used  to  a  considerable  ex- 
tent for  high-service  districts. 

DETAILS    OF    THE    WATER    END. 

The  water  end  of  a  direct-acting  or  crank  and  fly-wheel  pump 
served  as  the  pattern  for  power  pumps  for  many  years,  and  where 
large  volumes  of  water  must  be  handled  they  are  still  employed. 
Such  power  pumps  are  generally  driven  by  turbines  through  a 
train  of  powerful  gears,  and  all  parts  are  made  heavier  than  is  the 
case  of  similar  parts  of  a  direct-acting  pump.  In  the  latter  the 
steam  acts  as  a  cushion  to  take  up  jars  and  shocks,  but  in  the 
geared  power  pump  there  is  a  mass  of  non-compressible  water  in 
the  turbines  at  one  end  of  the  mechanism  and  another  mass  of 
water  in  the  pump  cylinders  at  the  other  end,  the  two  being  con- 
nected by  rigid  machinery  transmitting  stresses  instantly  from 
one  to  the  other  and  exposed  to  serious  accident  if  not  strong  and 
well  proportioned. 

These  water  ends  are  made  in  the  same  manner  as  the  ends  of 
steam  pumps,  and  it  is  therefore  appropriate  to  explain  a  few  of 
their  leading  features.  The  most  evident  characteristic  they 
have  is  the  piston  or  plunger  by  which  the  water  is  moved 
through  them;  an  inspection  of  Figure  28  will  show  the  differ- 
ence between  the  piston,  plunger  and  outside-packed  water  ends. 


WATER-WORKS    MANUAL. 


147 


The  first  is  used  in  small  pumps  almost  exclusively,  for  pumping 
gritty  water.,  and  for  pumping  against  a  long  suction  lift.  The 
The  second  is  the  usual  type  in  water-works  service.  The  third 
is  used  where  the  pump  handles  very  gritty  water  or  works  against 
unusually  heavy  heads,,  because  any  leakage  through  the  packing 
can  be  detected  at  once  and  remedied  more  easily  than  is  the  case 
with  the  other  types. 

The  valves  used  in  water-works  pumps  are  generally  disks  of 
India  rubber,  vulcanized  enough  to  give  firmness  yet  be  suffi- 
ciently elastic  to  permit  bending  at  right  angles  and  retain  their 


Plunger  Type.  Piston    Type. 

FIGURE  28. -TYPES  OF  PUMPS. 

shape.  They  are  held  against  their  seats  by  coiled  brass  springs 
and  move  vertically  on  a  spindle,  which  forms  part  of  the  seats. 
They  vary  in  thickness  from  half  an  inch  for  3-inch  valves  to 
three-fourths  of  an  inch  for  5-inch  disks.  They  are  a  very  im- 
portant part  of  the  pumps,  for  on  their  proper  size  and  working 
depends  in  a  large  measure  the  satisfactory  operation  of  the  whole 
apparatus.  In  Mr.  Barr's  book  on  pumping  machinery,  previ- 
ously referred  to,  the  following  statements  are  made:  "The  area 
of  clear  waterway  through  a  set  of  valves  in  a  water  end  should  be 
not  less  than  40  per  cent,  of  the  plunger  area  for  pumps  having 
a  speed  of  100  feet  per  minute;  and  if  that  speed  be  increased  to 


148  WATER-WORKS    MANUAL. 

say  125  feet  per  minute,  then  the  combined  water  areas  through 
the  valve  seats  should  be  50  per  cent,  of  the  plunger  area;  and  in 
like  manner  150  feet  per  minute  would  require  60  per  cent,  valve 
area,  175  feet  per  minute  would  require  75  per  cent,  valve  area, 
and  200  feet  per  minute  should  have  a  valve  area  equal  to  the 
plunger  area." 

The  pump  valve  problem  is  like  the  steam  safety  valve  prob- 
lem in  certain  respects,  and  there  are  many  different  opinions  con- 
cerning its  solution.  The  area  of  a  circular  port  varies  as  the 
square  of  its  diameter,  so  that  doubling  the  diameter  increases 
the  cross-section  of  the  waterway  four  times.  Hence  it  would  be 
an  easy  matter  to  furnish  ample  valve  area  were  this  the  only  fac- 
tor to  be  considered.  But  after  the  water  has  passed  through 
the  passage  it  must  flow  out  from  under  the  disk,  and  the  circum- 
ference of  the  circle  around  which  it  can  escape  increases  only  in 
the  same  ratio  as  the  diameter.  Hence  when  the  diameter  of  a 
passage  is  made  large  it  is  necessary  to  give  the  valve  covering  that 
passage  a  high  lift,  and  that  is  what  many  pump  makers  consider 
particularly  undesirable.  The  quicker  the  action  of  the  valves 
the  smoother  will  be  the  operation  of  the  pump,  and  it  is  for  this 
reason  that  a  number  of  small  valves  with  comparatively  low  lifts 
are  generally  preferred  to  a  few  large  valves  with  high  lifts. 
Sometimes  the  total  valve  area,  irrespective  of  the  lift  of  the 
valves,  is  too  small.  Mr.  Barr  describes  what  happens  in  this 
case  in  the  following  words:  "In  a  quick-running  pump  with  too 
small  a  valve  area  an  excessive  lift  is  required  of  the  valves,  so 
that,  in  the  interval  of  seating,  a  portion  of  the  water  in  the  pump 
cylinder  passes  under  the  valves  and  back  again  into  the  suction 
chamber;  at  the  moment  when  the  pressure  overtakes  the  valves 
in  their  downward  movement  the  velocity  is  so  greatly  accelerated 
as  to  force  them  violently  down  upon  their  seats,  the  pump  be- 
comes noisy,  and  nothing  will  relieve  the  pump  but  a  reduction 
in  the  speed  of  the  plunger,  suited  to  the  proper  and  noiseless 
action  of  the  valves.  Noisy  action  is  not  always  confined  to 
quick-running  pumps;  it  is  a  common  fault  with  nearly  all  low- 
priced  pumps,  the  temptation  evidently  being  to  put  in  larger 
water  plungers  than  the  valve  area  can  supply  at  the  common 
rating  of  100  feet  piston  speed  per  minute." 

The  unique  form  of  valve  designed  by  Prof.  Riedler  is  free 
from  many  of  the  limitations  of  the  usual  disk  valve,  and  merits 


WATER-WORKS    MANUAL.  149 

special  mention.  It  is  a  large  circular  valve  with  a  lift  of  1  to  2 
inches  and  replaces  the  entire  deck  of  valves  in  a  water  end  of  the 
customary  type.  It  opens  automatically  at  the  beginning  of  a 
stroke,  and  remains  open  until  the  end,  when  it  is  closed  posi- 
tively by  an  automatic  device.  In  this  way  no  limitation  is 
placed  on  the  piston  speed  of  the  steam  engine  by  slow  valve  ac- 
tion, and  the  whole  pumping  apparatus  can  be  run  at  the  speed 
which  gives  the  greatest  economy  in  the  consumption  of  steam. 
The  water  end  should  be  provided  with  valves  for  draining  it, 
and  a  connection  for  a  charging  pipe,  through  which  water  is  ad- 
mitted from  the  force  main  into  the  suction  chamber,  in  case  the 
charging  pipe  is  not  carried  directly  into  the  suction  pipe.  In 
crank  pumps  a  by-pass  connecting  the  two  ends  of  the  water  cyl- 
inder is  often  employed,  particularly  on  direct-pumping  service. 
This  by-pass  is  merely  a  small  pipe  from  1J  to  3  inches  in  diam- 
eter, by  which  part  of  the  water  forced  ahead  by  a  plunger  can  re- 
turn into  the  cylinder  behind  the  plunger,  thus  relieving  the  lat- 
ter of  considerable  work  yet  allowing  a  higher  piston  speed  than 
would  be  possible  otherwise.  In  case  a  compound  pump  is  work- 
ing against  a  high  pressure,  such  a  device  enables  the  engineer  to 
start  under  a  comparatively  light  load  and  run  in  this  way  until 
the  steam  end  is  in  a  condition  to  take  the  maximum  load.  With 
fly-wheel  pumps  working  under  very  much  lighter  loads  than  they 
were  designed  for,  the  opening  of  the  by-pass  prevents  the  irregu- 
lar operation  which  is  a  defect  of  some  pumps  of  this  class  under 
such  conditions.  The  charging  pipe  from  the  delivery  main,  pre- 
viously referred  to,  sometimes  connects  with  the  pipe  forming  this 
by-pass,  and  the  combination  is  often  called  the  priming  pipe  in 
consequence. 

SPECIAL    POWER    PUMPS. 

Power  pumps  of  small  capacity  are  now  generally  made  in  a  very 
different  form  from  that  of  the  water  end  of  a  direct-acting  pump. 
Three  cylinders,  usually  vertical,  are  employed,  and  for  this  rea- 
son the  pattern  is  called  triplex.  This  type  of  pump  has  been 
tried  by  many  years  of  service  under  harder  conditions  than  those 
of  town  water-works  and  has  grown  steadily  in  favor.  The  great- 
est trouble  with  them  in  the  past  has  probably  been  lack  of  suf- 
ficient valve  area,  although  complaint  has  been  made  against  the 
failure  of  some  makers  to  provide  means  of  taking  up  wear  in 
some  parts  of  the  apparatus.  This  has  prevented  running  at 


150 


WA  TER-WORKS    MANUA L. 


high  speeds  without  pounding,  and  hence  restricted  the  capacity 
of  the  pumps  to  lower  amounts  than  German  pumps  of  the  same 
stroke  and  diameter  of  plunger.  However,  the  attention  paid  to 
such  machinery  in  the  last  few  years  has  resulted  in  marked  im- 
provements. 

Until  within  a  short  time  the  three  cylinders  of  these  pumps 
were  single  acting,  and  each  discharged  water  during  but  half  a 
revolution  of  the  shaft  driving  its  plunger.  The  three  cranks  on 
the  shaft,  which  drive  the  plungers,  are  placed  at  angles  of 
120  degrees  with  each  other,  so  the  combined  discharge  of  the 
three  cylinders,  even  when  they  have  single  acting  plungers,  is 


Differential  Pump. 
FIGURE  29.— DIAGRAM  OF  CONSTRUCTION. 

approximately  uniform.  Triplex  pumps  have  lately  been  put  on 
the  market  in  which  this  discharge  is  still  more  uniform;  this  is 
obtained  by  the  use  of  differential  plungers.  As  these  are  also 
used  extensively  in  some  of  the  latest  sypes  of  vertical  engines,  a 
diagram  of  their  action  is  shown  in  Figure  29.  The  upward 
stroke  of  the  piston  draws  the  cylinder  full  of  water.  The  down- 
ward stroke  forces  this  water  through  the  passage  at  one  side  to 
the  discharge  opening,  where  some  of  it,  usually  one-half,  is 
driven  into  the  force  main  and  the  remainder  passes  into  the  top 
of  the  cylinder  above  the  piston.  The  piston  is  surmounted  by 
a  large  plunger  which  occupies  a  considerable  portion  of  the  cyl- 


WATER-WORKS    MANUAL.  151 

inder  space,  and  hence  does  not  let  all  the  water  discharged  by  the 
downward  stroke  of  the  piston  into  this  space.  On  the  next  up- 
ward stroke  of  the  piston  this  water  above  it  is  driven  out  while  a 
fresh  supply  is  coming  into  the  lower  part  of  the  cylinder  through 
the  suction  valves.  A  water  end  of  this  type  must  be  made  very 
strong  because  of  the  abrupt  change  in  direction  of  the  flow 
through  portions  of  it,  which  change  exposes  all  the  moving  parts 
to  shocks  of  considerable  magnitude  when  the  pump  is  working 
against  high  pressures. 

A  form  of  power  pump  which  has  made  some  strong  friends 
among  mining  and  irrigating  engineers  but  has  only  recently  been 
entered  as  a  competitor  among  water-works  apparatus  is  the  ro- 
tary. The  construction  of  these  pumps  is  so  well  explained  in 
the  trade  publications  of  the  makers  (see  the  advertising  columns 
of  "The  Engineering  Becord")  that  it  is  unnecessary  to  refer  to 
the  matter  here.  A  pair  of  these  pumps  was  installed  for  the 
Connersville,  Ind.,  water-works  in  1888.  One  of  them  is  used 
for  domestic  pressure,  45  to  60  pounds,  and  the  other  is  run  when 
a  fire  pressure  of  100  to  120  pounds  is  needed.  Each  is  driven  by 
an  independent  turbine  water  wheel,  that  for  the  fire  pump  be- 
ing considerably  larger  than  the  other.  After  running  about  five 
years  the  fire  pump  was  overhauled  at  the  request  of  the  water 
committee,  as  they  wished  to  have  the  apparatus  in  the  best  con- 
dition while  testing  some  new  water  mains.  No  repairs  were 
needed,  however,  until  the  plant  had  run  about  nine  years,  when 
the  shafts  had  to  be  replaced.  The  river  water  supplied  to  the 
city  is  at  times  quite  gritty,  but  in  spite  of  this  the  revolving  pis- 
tons had  worn  but  0.03  inch  in  their  nine  years  of  service.  The 
plant  requires  very  little  care.  For  several  years,  possibly  at  pres- 
ent also,  the  manager  of  the  plant  worked  full  time  in  a  furniture 
factory  adjoining  the  pumping  station,  and  the  pumps  looked 
after  themselves.  He  oiled  them  every  morning  before  going  to 
work,  and  in  case  a  fire  alarm  was  sounded  his  wife,  who  lived  in 
the  building,  went  down  stairs  and  started  the  fire  pump. 

Another  form  of  power  pump,  known  as  the  screw  pump,  is 
giving  good  satisfaction  under  pressure  of  less  than  150  pounds. 
It  is  comparatively  new  and  untried  for  water-works  purposes. 
Its  maker  is  selling  it  under  very  rigid  guarantees  as  to  its  effi- 
ciency, and  the  larger  sizes  seem  suited  for  use  in  the  class  of 
small  works  described  in  these  articles. 


152  WATER-WORKS    MANUAL. 

The  centrifugal  pump  is  rarely  used  in  water-works  for  the 
'main  pumping  engines,  owing  to  its  limited  forcing  power,  but  it 
is  admirably  adapted  for  raising  large  volumes  of  water  short  dis- 
tances, such  as  from  rivers  or  ponds  to  sedimentation  basins,  filter 
beds,  or  the  pump  wells  of  main  engines  where  very  long  or  other- 
wise unsatisfactory  suction  mains  are  necessary  without  such  pre- 
liminary pumping.  When  well  designed  and  not  overloaded 
their  efficiency  compares  favorably  with  that  of  other  power 
pumps  working  under  similar  conditions,  and  the  fact  that  grit 
and  sediment  in  the  water  have  little  effect  upon  them  renders 
them  especially  useful  in  handling  such  water  before  it  is  clarified. 
Where  the  pump  is  more  than  a  few  feet  above  the  water  it  is  best 
to  use  what  is  called  the  double-suction  type,  as  a  greater  efficiency 
is  probably  obtained  with  it  than  with  the  more  common  type. 
Centrifugal  pumps  are  proving  useful  at  the  bottom  of  open  wells, 
which,  for  one  reason  or  another,  have  been  reinforced  by  driven 
wells  sunk  in  their  bottoms.  These  wells  are  connected  to  a  cen- 
trifugal pump  at  the  bottom  of  the  open  well,  and  in  this  way 
the  volume  of  water  is  largely  increased  at  a  comparatively  small 
expense. 

Deep-well  pumps  are  often  operated  by  working  heads,  so 
called,  driven  by  stationary  engines,  and  where  economy  in  the 
use  of  fuel  is  particularly  desired  their  use  is  advisable.  The  or- 
dinary direct-acting  deep-well  pump  is  very  uneconomical  in  the 
use  of  steam,  as  already  mentioned,  compared  with  a  slide-valve 
engine  of  the  same  horse-power,  and  for  this  reason  the  addi- 
tional cost  of  the  plant,  consisting  of  slide-valve  engine,  belted 
or  connected  by  a  friction  clutch  to  a  working  head,  may  be  more 
than  met  by  the  reduced  fuel  expenses.  The  working  head  is 
also  useful  where  a  gasoline  engine  furnishes  the  power,  a  rapidly 
increasing  practice. 

The  principle  of  the  working  head  is  very  simple,  merely  the 
conversion  of  the  revolving  motion  of  a  pulley  into  the  recipro- 
cating motion  of  a  plunger  working  in  a  drop  tube  run  down  the 
well,  or  sometimes  in  the  tubular  casing  of  the  well.  There  are 
a  large  number  of  such  devices  on  the  market,  differing  only  in 
small  details.  In  selecting  one  care  should  be  taken  that  the 
wearing  surfaces  are  large  and  well  oiled  and  all  the  parts  are 
strong  and  heavy,  weight  being  of  importance  on  account  of  the 
tendency  of  the  head  to  shake  if  it  is  light  and  working  over  a 


WATER-WORKS    MANUAL.  153 

well  of  considerable  depth.  For  many  years  these  heads  had  a 
single  plunger  which  delivered  water  on  the  upward  stroke  only. 
Afterward  the  top  of  the  plunger  rod  was  provided  with  a  smaller 
plunger,  the  two  making  a  differential  plunger.  This  arrange- 
ment furnished  a  fairly  continuous  flow,  but  no  more  water  was 
obtained  than  with  the  original  device.  To  remedy  this  two 
plungers  were  introduced.  The  lower  one  has  a  solid  rod  run- 
ning down  from  the  head,  while  the  upper  one  is  provided  with 
a  hollow  rod  in  which  the  other  moves.  The  working  head  in 
this  case  is  arranged  so  that  one  or  the  other  piston  is  rising  prac- 
tically all  the  time  and  the  discharge  from  the  well  is  greatly  in- 
creased. A  recent  form  of  these  heads,  called  a  continuous-flow 
head,  is  designed  to  give  a  faster  speed  to  the  downward  than  the 
upward  stroke  of  each  plunger,  and  thus  render  the  flow  more 
uniform  than  with  the  older  type.  The  construction  of  these 
various  forms  of  heads  and  the  plungers  they  operate  are  so  clear- 
ly shown  in  the  trade  publications  of  the  makers  that  it  is  un- 
necessary to  illustrate  them  here. 

The  air-lift  pump  will  be  referred  to  in  the  next  chapter. 

It  sometimes  happens  that  a  small  district  which  must  be  sup- 
plied with  water  is  much  higher  than  the  remaining  portion  of 
the  town.  To  supply  all  the  consumers  with  water  under  the 
pressure  necessary  to  reach  these  few  elevated  houses  may  be  un- 
desirable on  account  of  the  heavy  pressure  it  will  put  on  most  of 
the  fixtures,  and,  if  all  the  water  is  pumped,  on  account  of  the 
disproportionate  expense.  In  such  a  case  several  plans  may  be 
followed.  If  the  town  has  an  electric  lighting  plant  its  simplest 
plan  will  be  to  install  a  power  pump  driven  by  an  electric  motor 
controlled  automatically  in  much  the  same  way  that  some  eleva- 
tor pumps  are  now  controlled.  This  pump  would  take  its  sup- 
ply from  the  nearest  main  to  the  hill.  Of  course,  a  steam  or  gas- 
oline engine  might  also  be  used,  and  a  tank  could  be  built  to 
store  enough  water  at  or  near  the  highest  point  to  prevent  any 
annoyance  in  case  of  accident  to  the  pumping  machinery.  In 
case  the  hill  is  on  the  line  of  the  force  main  or  the  chief  main  in 
the  case  of  a  gravity  supply,  a  water  motor  might  be  used  to  pump 
the  small  supply  needed  in  the  high  service  district.  There  are 
several  types  of  these  motors  on  the  market,  some  of  them,  like 
that  used  in  New  London,  Conn.,  described  in  "The  Engineering 
Record"  of  October  11,  1890,  being  very  interesting  mechanically. 


154  WATER-WORKS    MANUAL. 

SETTING    PUMPS. 

The  setting  of  the  pumps  and  their  connection  with  the  suc- 
tion and  delivery  pipes  is  generally  done  by  the  manufacturers, 
where  the  apparatus  is  of  fair  size,  say  500,000  gallons  or  more  in 
24  hours.  They  will  furnish  drawings  showing  the  size  of  the 
foundations  needed,  and  these  are  often  built  by  the  masons  who 
put  in  the  foundations  of  the  pumping  station,  but  if  the  pumps 
are  erected  by  the  manufacturers  it  is  advisable  to  put  the  respon- 
sibility of  the  foundations  on  them  also.  There  can  then  be  no 
question  as  to  who  is  liable  for  any  failure  in  the  operation  of  the 
machinery. 

The  manufacturers  also  furnish  tables  showing  the  smallest 
diameter  of  suction  main  to  be  used  with  any  pump,  and  if  this 
main  is  to  be  more  than  50  feet  long  or  to  have  any  bends  in  it, 
they  should  be  asked  to  select  the  proper  diameter,,  unless  the 
main  is  part  of  a  driven-well  plant,  in  which  case  it  should  be  de- 
signed so  that  the  greatest  velocity  of  the  water  in  it  at  any  point 
does  not  exceed  100  to  150  feet  per  minute,  depending  on  the 
readiness  with  which  the  wells  yield  the  water.  This  limit  to 
velocity  is  only  one-half  to  two-thirds  the  usual  velocity  in  suc- 
tion pipes,  but  it  is  desirable  with  tube  wells  in  order  to  keep  the 
friction  losses  between  the  well  strainers  and  the  pumps  as  small 
as  possible.  Flanged  cast  iron  pipes  make  the  best  suction  mains. 
They  should  be  laid  with  the  greatest  care  to  prevent  future  sink- 
ing at  any  point,  and  there  must  be  no  vertical  bends  in  which  air 
can  collect.  They  should  have  a  uniform  upward  grade  toward  the 
pumps  of  not  less  than  6  inches  in  100  feet,  and,  after  laying,  be 
tested  for  tightness  under  a  pressure  of  40  or  50  pounds.  A  leak, 
no  matter  how  small,  affects  the  pumps  badly.  It  is  usual  to  put 
a  foot-valve  at  the  inlet  of  the  suction  pipe  when  this  ends  in  a 
well,  in  order  to  keep  water  in  it  while  the  pump  is  idle,  and,  in 
case  the  pumps  work  against  heavy  pressure,  the  suction  pipe 
should  also  have  a  relief  valve.  This  prevents  serious  pressure 
coming  on  the  suction  pipe  in  case  the  pumps  are  stopped,  and 
leaky  valves  allow  the  pressure  in  the  force  main  to  be  communi- 
cated through  the  pump  to  the  suction  main.  A  strainer  is  used 
in  the  suction  main  whenever  there  is  any  probability  of  leaves  or 
similar  objects  reaching  the  pump;  this  strainer  is  placed  either  at 
the  end  of  the  suction  pipe  or  near  the  pump,  the  latter  location 
making  it  easier  to  clean  out  any  obstacles  which  may  be  caught. 


WATER-WORKS    MANUAL.  155 

If  the  suction  pipe  is  long  or  the  difference  in  elevation  be- 
tween its  ends  is  considerable,  it  should  have  a  vacuum  chamber 
as  near  the  pump  as  possible  to  keep  the  flow  in  the  suction  main 
uniform,  and  prevent  hammering  in  the  water  end.  The  pump 
is  similarly  provided  with  an  air  chamber  to  steady  the  flow  in  the 
delivery  main.  These  are  made  of  copper  for  small  pumps  and 
cast  iron  for  the  larger  sizes,  and  are  too  often  little  more  than  a 
hollow  mockery  owing  to  the  failure  of  the  manufacturers  to  pro- 
vide gauges  and  charging  apparatus  to  keep  them  full  of  air. 
The  capacity  varies  "from  four  to  fourteen  times  the  capacity  of 
the  barrel  of  the  pump/''  increasing  with  the  pressure  against 
which  the  pump  works;  there  are  a  few  manufacturers  who  do  not 
favor  them  except  under  high  pressures,  but  the  majority  regard 
them  as  valuable  under  all  conditions.  The  vacuum  chamber, 
when  one  is  used,  is  generally  about  half  the  size  of  the  air  cham- 
ber. An  important  paper  on  air  chambers  will  be  found  in  "The 
Engineering  Kecord"  of  September  13,  1890. 

The  force  main  should  have  a  gate  valve  and  a  check  valve,  the 
latter  as  near  the  pump  as  possible,  to  keep  the  pressure  in  the 
main  from  the  pump  while  it  is  idle.  A  small  charging  pipe,  al- 
ready mentioned,  is  attached  to  the  force  main  beyond  the  check 
valve  and  ends  either  in  the  suction  main  or  the  suction  chamber 
of  the  pump;  its  purpose  is  to  charge  the  suction  pipe  with  water 
when  the  pump  is  to  be  started.  In  order  to  allow  all  air  which 
may  have  found  its  way  into  the  pump  while  it  was  idle  to  escape 
and  so  prevent  the  jamming  of  the  valves,  it  is  necessary  to  have 
the  check  valve  in  good  condition  and  to  provide  a  small  starting 
or  waste  delivery  pipe  through  which  the  mingled  air  and  water 
of  the  first  few  strokes  may  be  discharged.  It  is  shut  off  as  soon 
as  the  pump  begins  to  run  smoothly.  These  different  attach- 
ments should  be  furnished  by  the  manufacturers  of  the  pumps 
and  set  up  by  them.  The  details  of  the  steam  piping  and  fre- 
quently of  the  boiler  plant,  are  left  to  them,  although  in  such 
cases  it  is  customary  in  advertising  for  bids,  to  state  that  any  or 
all  bids  may  be  rejected,  in  order  to  enable  the  water  commission- 
ers to  reject  low  tenders  based  on  unsatisfactory  apparatus.  It  is 
a  better  plan,  however,  to  retain  an  engineer  having  some  experi- 
ence with  pumping  plants  to  outline  the  features  of  the  desired 
plant  in  a  general  way  in  the  specifications,  and  determine  on  the 
test  necessary  for  its  acceptance.  This  enables  the  bidders  to 


156  WATER-WORKS    MANUAL. 

figure  on  about  the  same  class  of  machinery  and  workmanship, 
while  allowing  them  sufficient  latitude  to  use  their  special  feat- 
ures of  design.  As  regards  tests,  they  should  be  as  simple  as 
possible  for  the  class  of  works  under  discussion.  In  case  the 
pumping  machinery  is  purchased  under  a  guaranty,  a  test  should 
of  course  be  made  to  determine  whether  that  guaranty  has  been 
carried  out.  It  is  ridiculous  to  specify  certain  requirements  for 
pumps  and  then  fail  to  ascertain  whether  such  specifications  have 
been  fulfilled. 


CHAPTER  XIII.— THE  AIR  LIFT. 

The  air-lift  method  of  raising  water  is  by  no  means  new,  al- 
though made  a  commercial  success  within  a  comparatively  few 
years.  It  is  based  primarily  on  the  fact  that,  when  air  is  passed 
into  the  bottom  of  a  tube  submerged  in  water,  the  water  level  in 
the  tube  is  raised.  In  practice  the  wells  are  piped  in  various 
ways.  Sometimes  the  air  pipe  passes  down  the  center  of  the  well, 
and  the  water  is  forced  up  between  its  outside  surface  and  the 
casing;  sometimes  the  air  pipe  is  hooked  at  the  bottom,  and  its 
upward-pointing  nozzle  is  inserted  below  the  open  end  of  a  dis- 
charge pipe;  sometimes  the  discharge  pipe  is  inserted  within  the 
air  pipe,  and  the  air  passes  down  through  the  annular  space  be- 
tween the  two  to  suitable  orifices  near  the  bottom  of  the  inner 
tube;  sometimes  the  air  and  discharge  pipes  are  connected  by  a 
semicircular  bend,  from  the  lowest  point  of  which  a  single  pipe  is 
dropped  farther  down  the  well.  All  these  methods  are  further 
modified  by  the  use  of  special  nozzles  and  patented  features  con- 
trolled by  the  various  contractors.  The  latest  of  these  patented 
piping  arrangements  with  which  the  writer  is  acquainted,  con- 
sists of  the  well  casing  and  another  tube  nearly  as  large  and 
extending  into  the  water  a  considerable  distance,  the  space  be- 
tween the  two  forming  a  passage  for  air.  Inside  the  second  tube 
is  a  much  smaller  one,  down  which  still  more  air  can  be  forced, 
the  water  being  driven  up  between  it  and  the  intermediate  pipe. 
.The  small  central  pipe  has  apertures  at  different  elevations  which 
can  be  opened  separately  in  groups,  or  all  at  once,  by  an  ingenious 
arrangement  of  valves  operated  by  a  single  stem  and  a  handwheel 
at  the  top  of  the  well. 

The  arrangement  of  the  details  of  the  piping  is  always  left  to 
the  contractors,  for  their  practical  knowledge  generally  enables 
them  to  accomplish  the  required  result  with  the  minimum  amount 
of  experimenting.  The  theory  of  the  air  lift  is  chaotic,  and 
theoretical  designs  have  to  receive  considerable  practical  correc- 


158  WATER-WORK^    MANUAL. 

tion  before  they  will  work  satisfactorily.  Contractors  do  not  care 
to  call  general  attention  to  their  achievements,  as  their  competi- 
tors will  then  visit  the  plants  and  learn  the  secrets  of  the  success. 
There  are  some  remarkable  plants  in  this  country,  of  which  it 
was  hoped  the  builders  would  agree  to  furnish  reliable  informa- 
tion, but  they  have  all  declined  for  business  reasons. 

Prof.  Elmo  G.  Harris,  of  the  School  of  Mines  at  Kolla,  Mo., 
pointed  out  clearly  the  difficulties  in  the  way  of  a  satisfactory 
theoretical  discussion  of  the  air  lift,  in  the  "Journal"  of  the 
'  Franklin  Institute  for  July,  1895.  The  air  pressure  was  shown 
to  depend  on  the  depth  below  the  quiet  water  surface  at  which 
the  air  was  discharged,  and  on  the  velocity  of  the  water  at  this 
point.  The  slip  of  the  air  lift  is  a  very  important  factor;  it  is 
the  difference  in  velocity  of  the  air  bubbles  and  the  water  in  the 
discharge  tube,  and  depends  in  a  large  measure  on  the  volume  of 
each  individual  bubble  and  hence  on  the  form  and  area  of  the  air 
inlet.  The  net  lift  is,  of  course,  an  important  factor,  and  the 
area  of  the  discharge  pipe  also  affects  the  results.  Finally,  the 
ratio  of  the  expansion  of  the  air  as  it  rises  through  the  main  pipe 
and  the  total  volume  of  air  in  this  pipe  cannot  be  changed  with- 
out affecting  the  efficiency  of  the  plant.  In  a  general  way  it  may 
be  said  that  the  present  practice  is  to  submerge  the  main  pipe 
about  a  thirc  or  half  again  as  deep  as  the  net  lift  from  the  water 
to  the  point  of  discharge,  and  to  use  just  enough  air  pressure  to 
overcome  the  pressure  of  the  water  column.  More  pressure  jvill 
give  more  water,  but  the  cost  per  thousand  gallons  will  be  in- 
creased. The  piping  is  generally  altered  a  number  of  times  be- 
fore the  best  form  is  determined.  In  case  a  number  of  wells  are 
to  be  pumped,  it  is  strongly  recommended  that  a  valve  be  placed 
on  the  air  line  near  each  well  rather  than  near  the  receiver  from 
which  the  air  is  delivered. 

The  air  compressor  for  an  air-lift  plant  should  be  selected  care- 
fully, as  upon  it  will  depend  in  a  large  measure  the  satisfactory 
operation  of  the  station.  It  would  be  out  of  place  to  discuss  com- 
pressors in  this  place,  particularly  as  Mr.  Frank  Eichards  has  al- 
ready done  this  in  his  valuable  book  entitled  "Compressed  Air," 
but  a  few  general  statements  are  necessary  for  an  elementary  dis- 
cussion of  the  subject  in  hand.  In  the  first  place,  when  air  is 
compressed,  part  of  the  work  done  in  the  steam  cylinders  is  lost 
in  a  number  of  ways.  From  5  to  20  per  cent,  may  be  spent  to 


WATER-WORKS    MANUAL.  159 

overcome  the  friction  of  the  compressor,  and  it  is  here  that  good 
workmanship  keeps  down  the  waste.  From  5  to  20  per  cent, 
more  may  he  lost  in  heating  the  air  in  entering  and  by  clearance, 
a  loss  which  good  design  diminishes.  Finally  from  15  to  35  per 
cent,  is  inevitably  lost  by  heating  the  air  during  its  compression, 
for  it  is  impracticable  to  keep  the  air  at  a  constant  temperature 
while  its  volume  is  being  reduced  and  its  pressure  raised.  The 
last  loss  is  an  important  one  when  the  compressed  air  is  to  be  used 
to  lift  water. 

Just  how  much  drop  there  is  in  the  temperature  of  the  com- 
pressed air  from  the  time  it  leaves  the  cylinders  until  it  mingles 
with  the  water  in  the  well  depends  on  a  number  of  circumstances. 
"Where  the  air  is  compressed  to  75  pounds  and  the  water  in  the 
well  is  at  45  degrees  Fahrenheit,  the  fall  in  temperature  is  about 
350  degrees.  It  has  already  been  stated  that  part  of  the  work 
done  in  the  steam  cylinders  is  spent  in  raising  the  temperature  of 
the  air,  so  if  the  latter  is  subsequently  cooled  350  degrees,  all  the 
work  done  in  raising  its  temperature  this  amount  is  necessarily 
lost.  Under  the  conditions  mentioned  the  loss  will  be  about  23 
per  cent.  For  many  purposes  to  which  compressed  air  is  put  this 
waste  of  energy  is  partly  avoided  by  reheating  the  air  before  using 
it,-  but  this  remedy  is  useless  in  air-lift  plants. 

It  is  evident  that  in  stations  for  pumping  water  it  is  particu- 
larly important  to  keep  the  final  temperature  of  the  compressed 
air  as  low  as  possible.  There  are  three  means  of  doing  this. 

The  first  is  by  cooling  the  air  during  compression,  by  selecting 
suitable  forms  of  compressors.  Such  machinery  may  be  classed 
as  wet  or  dry,  according  as  water  is  or  is  not  present  in  the  air 
cylinders  during  compression.  There  are  two  distinct  types  of 
the  wet  compressor.  In  the  first  the  water  enters  the  cylinder 
with  the  air,  and  in  the  second  it  is  sprayed  through  the  air  dur- 
ing compression.  The  first  type  is  inefficient  because  the  water 
does  not  cool  the  air  very  much  and  merely  runs  in  and  out  of  the 
cylinder  as  if  the  machine  were  a  pump.  The  second  type  is  the 
most  efficient  compressor  there  is,  so  far  as  delivering  cool  air  is 
concerned,  but  the  parts  wear  out  too  rapidly  to  make  it  a  com- 
mercial success.  American  compressors  are  now  of  the  water- 
jacketed  type,  and  what  cooling  is  accomplished  is  effected  by 
circulating  cold  water  over  the  outside  of  the  cylinders  in  which 
the  air  is  compressed.  They  consequently  give  cooler  air  vhen 


160  WATER-WORKS    MANUAL. 

run  at  low  than  high  speeds.  The  volume  of  a  cylinder  is  propor- 
tional to  the  square  of  its  diameter,  while  the  cooling  surface  is 
proportional  to  the  first  power  of  the  diameter,  hence  compres- 
sors built  with  a  large  number  of  small  air  cylinders  immersed 
in  water  should  give  unusually  cool  air.  Such  machines  have 
been  built  and  give  the  expected  results,  but  their  complexity 
has  prevented  their  general  use. 

The  second  method  of  keeping  down  the  final  temperature  of 
the  compressed  air  is  by  raising  the  pressure  in  stages  and  cooling 
it  between  the  successive  stages.  It  may  be  said  in  a  general  way 
that  the  best  current  practice  is  to  use  two  stages  when  the  final 
pressure  is  between  60  and  300  pounds,  and  three  stages  when  it 
is  between  300  and  1,000  pounds.  Two-stage  compression  to  75 
pounds  means  a  saving  of  about  17  per  cent,  over  single-stage,  and 
three-stage  compression  to  500  pounds  means  a  saving  of  25  per 
cent,  over  single-stage. 

The  third  method  is  to  take  the  air  as  cool  as  it  is  possible  to 
obtain  it.  About  1  per  cent,  is  saved  for  each  5  degrees  fall  in 
temperature  of  the  free  air  entering  the  compressors.  During 
the  winter  months  a  considerable  economy  can  be  effected  by 
drawing  the  air  from  outside  the  station  building,  but  if  this  is 
done  care  must  betaken  to  make  the  flues  to  the  inlets  large  and 
free  from  bends.  The  writer  knows  of  no  air-lift  plant  where 
this  is  done,  and  it  would  probably  prove  an  uneconomical  .  re- 
finement in  many  small  plants.  At  La  Grange,  111.,  a  connection 
was  made  from  the  well  casing  to  a  cylindrical  drum  about  18 
inches  in  diameter  and  8  or  10  feet  high.  From  the  side  of  this 
drum  the  water  discharged  from  the  well  was  taken,  and  from 
the  top  was  led  an  air  pipe  to  the  intake  of  the  air  compressor. 
The  air,  after  doing  its  work  in  the  well,  is  reduced  to  the  tem- 
perature of  the  water,  and  is  returned  to  the  compressor  at  about 
30  degrees  lower  temperature  than  the  engine  room.  A  two-day 
test  of  the  plant,  the  first  day  drawing  the  air  from  the  engine 
room  and  the  second  day  from  the  well,  showed  that  about  6  per 
cent,  less  coal  was  needed  when  the  air  from  the  well  was  used. 

A  receiver  should  always  be  placed  near  the  compressor  to  hold 
the  air.  It  equalizes  the  work  of  the  compressor  in  much  the 
same  way  as  the  air  chamber  on  a  force  main,  and  also  acts  as  a 
separator  to  catch  the  water  and  oil  which  are  carried  by  the  air. 
These  are  blown  out  at  frequent  intervals.  As  regards  the  pip- 


WATER-WORKS    MANUAL.  161 

ing,  the  following  hints  are  quoted  from  a  lecture  by  Mr.  William 
Prellwitz,  of  the  Ingersoll-Sergeant  Drill  Company,  before  the 
students  of  Lafayette  College:  "All  pockets  in  pipe  lines  should 
be  avoided,  as  they  have  a  tendency  to  hold  water,  and  thus  re- 
tard the  free  passage  of  the  air.  Should  it  become  necessary  to 
pass  air  through  a  pipe  line  which  must  of  necessity  have  many 
pockts  in  it,  these  may  hold  so  much  water  that  very  little  air 
pressure  will  be  had  at  the  end  of  the  line.  Where  these  condi- 
tions exist  much  trouble  can  be  avoided  by  thoroughly  cooling 
the  air,  thereby  taking  out  all  its  moisture,  to  a  temperature  lower 
than  that  of  the  pipe  through  which  it  will  pass,  so  that  the  air 
will  have  a  tendency  to  take  up  moisture  in  the  pipe  instead  of 
dropping  its  water  in  it." 

The  efficiency  of  the  air  lift  depends  on  so  many  factors,  which 
are  only  now  beginning  to  be  understood,  that  the  apparatus  has 
been  regarded  as  extremely  uneconomical.  It  certainly  is  not  so 
economical  for  high  lifts  as  some  of  the  latest  forms  of  power- 
pumps  or  as  plunger  pumps  inserted  in  a  pit.  On  the  other  hand, 
a  deep  well  of  small  diameter  costs  much  less  than  a  larger  one, 
and,  if  the  well  discharges  freely,  the  extra  cost  of  air  pumping 
may  not  be  so  great  as  the  extra  cost  of  the  large  well.  This  is 
particularly  important  where  the  plant  is  a  small  one  and  is  oper- 
ated intermittently.  A  particularly  useful  field  of  the  air  lift  is 
in  gauging  wells  to  ascertain  their  maximum  yield,  on  account 
of  the  readiness  with  which  the  conditions  may  be  changed  by 
altering  the  piping  or  changing  the  speed  of  the  compressor. 

While  the  efficiency  of  the  air  lift  is  under  consideration,  at- 
tention is  drawn  to  the  accompanying  table  of  the  results  of  a 
number  of  tests  conducted  under  the  direction  of  Mr.  F.  A.  W 
Davis,  of  the  Indianapolis  Water  Company.  The  well  was  10 
inches  in  diameter  and  330  feet  deep,  and  was  tested  by  measur- 
ing the  time  it  took  to  fill  a  tank  holding  267  cubic  feet,  under 
the  conditions  given  in  the  table.  The  air  was  measured  by  a 
Wilie  proportional  gas  meter  and  the  figures  give  the  volume  of 
compressed  and  not  free  air.  The  temperature  of  the  air  as  it 
came  from  the  compressor  was  176  to  177  degrees,  and  that  of  the 
water  as  it  emerged  from  the  well  was  54  degrees.  The  aeration 
of  the  water  by  the  lift  caused  it  to  precipitate  the  iron  in  solu- 
tion, an  advantage  of  this  method"  of  raising  water  noticed  in 
other  plants. 


162  WATER-WORKS    MANUAL. 

Test  of  Air  Lift,  Indianapolis. 
Pumpage.  Air. 

Discharge 


Ti 

me. 

per 

Amount. 

Fressui 

minute. 

Min. 

Sec. 

Cu.  ft. 

Cu.  ft. 

Lbs. 

2 

19.5 

115 

152 

36 

<5 

12 

121 

150 

36 

2 

16 

118 

146 

36 

2 

21 

114 

140 

37 

2 

46 

96 

255 

46 

3 

55 

68 

240 

46 

1 

53 

142 

100 

44 

1 

50 

146 

101 

44 

1 

35 

169 

100 

50 

1 

45 

152 

100 

43 

I 

43 

155 

100 

43 

1 

45 

153 

100 

45 

1 

37 

165 

100 

44 

*1 

55 

139 

106 

45 

*1 

54 

141 

107 

45 

**! 

48 

148 

99 

43 

**! 

47 

150 

96 

46 

Depth  in 
water. 
Ft. 
64.3 


41.3 

82.7 
102.2 


83.6 


80.7 


Piping. 

Height 

above 

water. 

Ft. 

25.7 


25.7 

27.3 
27.8 


27.3 
27.3 


Note. — The  first  13  tests  were  made  with  a  21/£-inch  air  pipe;  those 
marked  *  with  a  4-inch  pipe;  those  marked  **  with  a  2^-inch  pipe 
having  a  curved  nozzle  deflecting  the  air  upward. 

At  a  meeting  of  the  Western  Society  of  Engineers,  held  March 
3.  1897,  there  were  many  statements  made  concerning  the  field  of 
the  air  lift  and  its  advantages,,  to  which  attention  is  drawn.  The 
full  discussion  will  be  found  in  the  society's  "Journal"  of  April, 
1897. 

Mr.  Thomas  T.  Johnston. — "In  almost  all  cases  the  air  lift  is 
used  to  raise  water  to  the  surface  of  the  ground  and  no  higher. 
It  might,  in  some  cases,  be  used  to  raise  water  to  a  tower  above 
the  ground,  but  its  efficiency  falls  off  so  rapidly  as  the  head 
pumped  against  increases,  that  it  is  better  to  raise  the  water  to 
the  surface  only,  and  to  pump  from  the  surface  to  the  stand-pipe 
or  into  the  mains  by  ordinary  plunger  pumps.  It  is  also  neces- 
sary to  allow  the  water  to  free  itself  from  air  before  it  enters  the 
mains.  Since  the  practical  case  may  be  assumed  to  involve  lift- 
ing water  to  a  height  above  the  surface,  an  air-lift  plant  will  be 
considered  to  include  not  only  the  compressor,  receiver,  piping, 
reservoir,  etc.,  but  also  the  pump  and  appurtenances.  The  effi- 
ciency of  the  plant  must  involve  the  expenses  due  to  double 
pumping. 

"It  has  been  a  common  claim  for  the  air  lift  that  wherever  ap- 
plied it  has  resulted  in  an  increased  flow  from  the  well.  This  has 
undoubtedly  been  the  fact  in  a  great  many  cases.  Take  the  case 


WATER-WORKS  MANUAL.  163 

of  the  well  in  question,  for  instance,  and  the  diameter  of  the  well 
tube  to  be  anything  less  than  12  inches.  It  would  not  be  pos- 
sible to  insert  in  the  tube  either  an  old-fashion  or  continuous- 
flow  deep-well  pump  having  a  capacity  of  500,000  gallons  per  day. 
Neither  of  these  pumps  could  reduce  the  pressure  at  a  point  50 
feet  below  the  surface  to  that  of  the  atmosphere.  The  air  lift 
could  do  so,  however,  and  would  thus  be  able  to  derive  more 
water  from  the  well  than  either  of  the  other  pumps.  If,  how- 
ever, the  well  tube  were  15  inches  or  more  in  diameter  for  30  or 
40  feet  below  the  surface,  then  the  continuous-flow  pump  would 
come  into  the  field  and  raise  the  water  with  much  higher  econ- 
omy than  the  air  lift.  Or,  if  the  conditions  be  favorable,  plunger 
pumps  in  a  pit  30  feet  deep  would  do  the  same  thing  with  more 
economy  doubtless  than  either  the  air-lift  or  continuous-flow 
pump.  There  is  nothing  inherent  in  the  air  lift  that  causes  an 
increased  flow  from  a  well,  though  under  certain  conditions  it  is 
capable  of  producing  that  result.  The  continuous-flow  pump 
method  requires  only  a  sufficiently  large  well  tube,  and  the  pit 
method  requires  only  a  sufficiently  deep  pit. 

"It  must  be  evident  that  no  general  rule  can  be  laid  down  to 
determine  the  best  method  of  pumping  to  adopt  for  any  or  all 
wells.  The  conditions  surrounding  any  particular  case  may  vary 
so  widely  from  those  of  another  case  that  what  may  be  suited  to 
one  will  not  be  of  any  use  for  the  other.  It  can  be  said  in  gen- 
eral that  when  large  water  supplies  are  involved,  for  cities  of  20,- 
000  inhabitants  or  more,  and  where  atmospheric  pressure  in  wells 
must  be  made  to  occur  at  levels  below  the  surface  of  the  ground, 
the  pit  method  is  the  most  advantageous.  For  very  small  sup- 
plies, where  the  total  amount  of  money  involved  is  not  a  large 
item  in  any  event,  and  where  economy  in  operation  is  not  a  mat- 
ter of  moment,  the  air-lift  and  old-fashion  deep-well  pump  may 
find  useful  application.  The  intermediate  field  affords  opportu- 
nity for  strife  between  the  pit  method  and  the  continuous-flow 
pump  in  a  degree  varying  with  the  several  conditions  of  any  par- 
ticular case." 

Mr.  •  J.  F.  Lewis. — "The  advantages  of  the  air  lift  are  that  the 
machinery  is  all  above  ground  and  concentrated  so  as  to  require 
less  attendance  than  any  other  system,  a  great  increase  of  water, 
and  no  repairs  whatever.  If  the  water  falls  in  the  well  it  can  be 
followed  down,  and,  by  installing  an  economical  compressor  with 


164  WATER-WORKS  MANUAL. 

a  compound  condensing  Corliss  engine  and  compound  air  cylin- 
ders, with  the  new  systems  of  piping  the  wells,  there  is  no  ques- 
tion but  what  the  cost  per  million  gallons  will  compare  favorably 
with  any  system  that  is  in  vogue." 

Mr.  D.  W.  Mead. — "The  air-lift  system  has  its  chief  use  when 
the  quantity  of  water  is  the  chief  concern,,  and  where  this  is  to  be 
taken  from  single  wells  and  the  cost  of  operation  is  not  a  large 
consideration.  It  is  the  best  combination  pumping  appliance 
which  has  been  placed  on  the  market  for  obtaining  a  large  quan- 
tity of  water  from  a  small  hole.  For  instance,  some  preliminary 
experiments  were  made  with  the  air  lift  on  a  well  at  Rockford,  111. 
This  is  an  8-inch  well  drilled  into  the  Potsdam  sandstone  and 
flows  at  the  surface.  It  flowed  at  the  outlet  of  the  discharge  pipe 
about  150  gallons  per  minute.  When  the  air  lift  was  started  with 
a  6-inch  pipe  inside  the  8-inch  casing,  the  amount  of  water  was 
increased  to  about  650  gallons  per  minute,  and  when  the  6-inch 
pipe  was  taken  out  and  the  8-inch  casing  used  as  the  discharge 
outlet,  the  discharge  was  increased  to  over  900  gallons  a  minute. 
It  is  probably  impossible,  with  an  ordinary  power  pump,  to  obtain 
such  a  large  dicharge  from  a  small  hole  as  this  experiment  shows, 
and,  in  places  where  it  is  a  question  of  volume  and  not  economy, 
the  air  lift  has  this  advantage  over  anything  else  that  has  been 
offered." 


CHAPTER  XIV.— PUMPING  STATIONS. 

In  designing  a  pumping  station  it  is  not  enough  to  provide 
machinery  which  will  furnish  a  certain  quantity  of  water  daily. 
That  is  easily  done,  but  it  is  not  such  a  simple  task  to  design  works 
which  will  be  the  most  economical  in  operation  during  the  whole 
of  their  period  of  service.  Such  a  plant  is  laid  out  with  a  view  to 
using  the  most  available  fuel  in  the  most  economical  manner,  and 
the  utilization  of  the  steam  by  engines  and  accessories  of  such 
types  that  any  further  additions  to  the  plant  will  cost  more  than 
they  will  save.  The  evaporative  efficiency  of  various  coals  ranges 
widely  and  the  furnaces  to  get  the  best  results  from  one  fuel  are 
different  from  those  for  another;  hence  the  best  plant  for  one 
locality  may  be  far  from  the  best  for  another,  although  the  'amount 
and  pressure  of  the  steam  are  the  same  in  both  cases.  Before  the 
plans  of  a  permanent  power  plant  are  finally  adopted,  it  is  there- 
fore very  desirable  to  have  them  examined  by  some  one  thoroughly 
acquainted  with  such  work,  for  his  suggestions  may  result  in  a 
saving  of  far  more  money  than  his  fee. 

While  it  would  be  useless  to  attempt  in  this  place  to  discuss  the 
economical  features  of  the  different  classes  of  pumping  machinery, 
nevertheless  the  stations  themselves  may  be  considered  in  a  gen- 
eral way.  In  the  first  place,  it  is  important  to  determine  the  ad- 
visability of  combining  a  water-pumping  and  electric  station  in 
one  plant.  This  is  now  frequently  done,  as  at  the  Greenwich, 
Ohio,  plant  shown  in  Figure  30,  which  was  designed  by  Mr.  Burton 
J.  Ashley.  The  water  at  this  plant  is  forced  by  a  500,000  gallon 
pump  to  a  100  x  11-foot  standpipe.  There  is  a  100-horse-power 
engine  running  at  180  revolutions  per  minute  and  belted  to  a  40- 
light  dynamo  for  arc  lights  and  a  500-light  dynamo  for  the  in- 
candescent service. 

Between  such  a  plant  and  the  pumping  station  at  Walpole, 


WATER-WORKS    MANUAL. 


8'Suctionc+A  f  &"  Discharge. 


Vertical    Section. 


Plan. 
FIGURE  30.— WATER  AND  ELECTRIC  STATION,  GREENWICH. 


WATER-WORKS  MANUAL.  167 

Mass.,  shown  in  Figure  31,  there  is  a  wide  variety  of  intermediate 
types  which  it  would  be  fruitless  to  discuss.  The  Walpole  plant, 
designed  by  Mr.  Freeman  C.  Coffin,  is  a  building  with  14-inch 
brick  walls  and  a  slate  roof  carried  by  wood  trusses.  The  floor 
of  the  engine  room  is  6  inches  of  hydraulic  cement  covered  with 
1  inch  of  asphalt.  The  boiler  room  has  a  floor  of  hard  brick  laid 
on  edge  in  cement  on  3  inches  of  sand.  The  water  is  drawn  from 
driven  wells  through  a  sand  catcher  into  a  surface  condenser  and 
thence  to  the  pumping  engine.  The  sand  catcher  also  serves  to 
intercept  the  air  from  the  wells,  which  is  removed  by  the  small  air 
pumps  mounted  on  its  top.  The  steam  from  the  feed,  air  and 
main  pumps  passes  through  a  horizontal  heater,  and  then  through 
the  surface  condenser  before  it  is  pumped  into  the  hot  well.  In 
this  plant  a  duplex  pump  is  used;  if  a  fly-wheel  pump  were  em- 
ployed a  separator  would  be  placed  on  the  steam  pipe  to  prevent 
water  entering  the  cylinders,  which  is  a  serious  matter  with  such 
pumps,  but  less  important  with  the  duplex  type.  The  carpentry 
and  masonry  in  such  a  building  are  matters  with  which  every 
builder  is  acquainted  and  do  not  require  discussion. 

Where  vertical  pumps  are  employed  a  dry  well  is  necessary  to 
contain  the  water  cylinders,  and  this  sometimes  involves  more 
trouble  in  construction  than  any  other  portion  of  the  plant.  If 
the  amount  of  water  which  it  is  expected  to  encounter  is  large,  it 
may  be  advisable  to  sink  the  wall  on  a  curb  in  the  manner  already 
described  for  open  wells,  laying  the  masonry  with  great  care  as  the 
curb  sinks.  When  the  necessary  depth  has  been  reached  the 
bottom  can  be  dredged  out  to  a  fairly  level  surface  and  then  cov- 
ered with  quick-setting  Portland  cement  concrete  deposited  under 
water  by  buckets  or  otherwise.  If  the  work  is  done  carefully  and 
no  attempt  made  to  pump  out  the  water  until  the  concrete  has  set, 
it  will  very  likely  be  possible  to  make  a  fairly  dry  well  in  this  way 
which  can  be  made  water-tight  afterward  by  a  rendering  of  ce- 
ment, an  asphalt  coat  or  a  carefully  laid  brick  lining.  A  number 
of  hints  for  the  use  of  asphalt  as  a  water-proofiing  material  are 
given  in  Chapter  XVIII.  under  the  head  of  asphalt-lined  reser- 
voirs. 

What  is  known  as  the  Sylvester  process  of  water-proofing  is 
sometimes  used  for  such  work.  The  dry-well  of  the  new  Steuben- 
ville  water-works,  designed  by  Messrs.  Wilkins  &  Davison,  affords 
an  instance.  The  wall  of  this  well  is  3  feet  thick  at  the  bottom 


WATER-WORKS    MANUAL. 


WATER-WORKS    MANUAL.  169 

and  2  feet  at  the  top,  and  consists  of  a  9-inch  outer  ring,  a  2--inch 
filling  of  Portland  cement  mortar,  and  an  inner  ring.  The  specifi- 
cation for  the  water-proofing  reads  as  follows:  "When  the  walls 
have  thoroughly  dried  out  the  inside  shall  be  coated  with  a  solu- 
tion of  Castile  soap,  three-quarters  of  a  pound  to  one  gallon  of  hot 
water.  This  shall  be  applied  while  hot.  After  remaining  24 
hours  there  shall  be  applied  a  second  coat  composed  of  half  a 
pound  of  alum  to  4  gallons  of  water,  then  another  coat  of  soap 
solution,  and  finally  a  second  coat  of  alum  solution,  24  hours  to 
elapse  between  each  coat." 

So  little  has  recently  been  printed  about  this  process  that  it  may 
be  well  to  reprint  in  this  place  a  description  of  its  use  in  water- 
proofing a  gate-chamber  of  the  Croton  Keservoir  in  Central  Park, 
New  York.  This  was  written  by  the  late  W.  L.  Dearborn  and 
printed  in  the  first  volume  of  the  "Transactions"  of  the  American 
Society  of  Civil  Engineers.  The  gate-chamber  in  question  was 
built  of  the  best  quality  of  hard-burned  brick  laid  in  a  mortar  of 
one  part  Eosendale  cement  and  two  parts  of  sand.  Concrete  fill- 
ing was  placed  between  the  brick  walls  and  the  latter  were  laid 
with  great  care,  but  when  the  chamber  was  put  in  service  under  a 
head  of  36  feet  water  passed  through  the  masonry  in  considerable 
quantities.  Mr.  Dearborn's  description  of  the  process  of  water- 
proofing is  as  follows: 

"The  process  consists  in  using  two  washes  or  solutions  for  cover- 
ing the  surface  of  the  walls — one  composed  of  Castile  soap  and 
water,  and  one  of  alum  and  water.  The  proportions  are  three- 
quarters  of  a  pound  of  soap  to  one  gallon  of  water  and  half  a  pound 
of  alum  to  4  gallons  of  water,  both  substances  to  be  perfectly  dis- 
solved in  water  before  being  used.  The  walls  should  be  perfectly 
clean  and  dry,  and  the  temperature  of  the  air  not  below  50  degrees 
Fahrenheit  when  the  solutions  are  applied. 

"The  first  or  soap  wash  should  be  laid  on  when  boiling  hot  with 
a  flat  brush,  taking  care  not  to  form  a  froth  on  the  brickwork. 
This  wash  should  remain  24  hours  so  as  to  become  dry  and  hard 
before  the  second  or  alum  wash  is  applied,  which  should  be  done 
in  the  same  manner  as  with  the  first.  The  temperature  of  this 
wash,  when  applied,  may  be  60  or  70  degrees,  and  it  should  also 
remain  24  Hours  before  a  second  coat  of  the  soap  wash  is  put  on. 
These  coats  are  to  be  applied  alternately  until  the  walls  are  made 
impervious  to  water.  The  alum  and  soap  thus  combined  form  an 


170  WATER-WORKS    MANUAL. 

insoluble  compound,  filling  the  pores  of  the  masonry  and  entirely 
preventing  the  water  from  entering  the  walls. 

"As  this  experiment  was  made  in  the  fall  and  winter,  1863,  after 
the  temporary  roofs  were  put  on  the  gate-house,  artificial  heat  had 
to  be  resorted  to  to  dry  the  walls  and  keep  the  air  at  the  proper 
temperature.  The  cost  was  10  cents  per  square  foot.  As  soon 
as  the  last  course  had  become  hard,  the  water  was  let  into  the  bays 
and  the  walls  were  found  to  be  perfectly  impervious  to  water,  and 
the'y  remain  so  in  1870,  after  about  6^  years." 

It  has  already  been  shown  that  pumps  drawing  their  supplies 
from  driven  wells  should  be  placed  as  low  as  possible  in  order  to 
reduce  the  suction  head  to  the  minimum.  A  low  suction  head  is 
far  more  important  with  these  wells  than  where  the  supply  is 
drawn  from  an  open  wet  well,  because  of  the  air  which  is  present 
in  the  ground  water.  Horizontal  pumps  were  the  only  type  for- 
merly used  for  small  works  and  an  open  pit  large  enough  to  con- 
tain them  was  frequently  an  expensive  undertaking.  The  intro- 
duction of  power  pumps  now  makes  it  possible  to  keep  the  engines 
on  the  main  floor  of  the  building  and  put  the  pumps  as  low  as 
seems  desirable. 

The  pumping  at  Tarboro,  N.  C.,  affords  a  good  illustration  of 
such  a  plant.  The  old  works  owned  by  the  town  had  a  40-horse- 
power  boiler  and  a  12  x  7  x  12-inch  duplex  pump,  the  latter  in  a 
pit  5  feet  below  the  floor  line.  The  works  recently  passed  into 
the  hands  of  a  private  company  and  their  present  condition  is 
shown  in  Figure  32.  Mr.  J.  W.  Ledoux,  chief  engineer  of  the 
American  Pipe  Manufacturing  Company,  which  built  the  plant, 
informed  the  writer  in  1897  that  the  water  was  drawn  from  eleven 
tube  wells  along  the  bank  of  Hendrick's  Creek,  and  could  be  sup- 
plemented by  a  separate  connection  with  the  latter,  which  has  a 
drainage  area  of  nearly  10  square  miles.  The  power  is  furnished 
by  two  gasoline  engines  of  13^  actual  horse-power  each,  running 
at  250  revolutions  per  minute  and  belted  to  two  7  x  7-inch  triplex 
pumps  running  at  40  revolutions  per  minute.  The  pumps  were 
placed  on  a  level  with  the  top  of  the  driven  wells  and  the  engines 
are  6  feet  higher,  on  the  same  floor  line  as  the  steam  pump. 

The  pumping  chamber  has  a  semi-circular  22-inch  brick  wall 
laid  in  Portland  cement,  and  the  floor  is  2  J  feet  of  concrete  fin- 
ished with  pure  cement.  Being  close  to  the  creek,  which  often 
rises  to  a  depth  of  15  feet,  the  outside  of  the  pumping  chamber 


WATER-WORKS    MANUAL.  171 

was  protected  by  10-inch  pine  piles  driven  close  together  to  a 
depth  of  about  15  feet.  The  building  is  hard  brick  with  a  metal- 
shingled  roof. 

All  the  stations  constructed  by  Mr.  Ledoux  are  notable  for  the 
care  taken  to  make  them  attractive  to  visitors.  The  writer  has 
been  able  to  secure  no  satisfactory  view  of  the  interior  of  the  Tar- 


Pump  Room  Floor  Linz.-^^-- 


Scale 
O'     4'      &'     12'     16'   2<p/ 


Elevation . 


Level  of  Bottom  of  Piles. 

FIGURE  32.  -  TARBORO  PUMPING  STATION. 


boro  station,  but  Figure  33  shows  the  general  finish  of  his  plant 
at  Westville,  N".  J.  The  contractor  for  the  pumping  plant  at 
both  these  places.,  Mr.  W.  P.  Dallett,  used  Otto  engines  and  Dem- 
ing  pumps.  The  appearance  of  the  engines  suggests  a  show  room 
rather  than  a  money-making  plant,  yet  it  is  highly  probable  such 
attractive  surroundings  lead  the  engineers  to  keep  machinery  in 
better  condition  than  when  it  is  placed  in  a  frame  building  with 
a  board  floor  and  rough  finish. 

An  innovation  of  recent  date  in  lighting  small  pumping  stations 
is  the  use  of  incandescent  lamps  furnished  with  current  by  a  dyna- 
mo driven  by  a  small  impulse  water-wheel.  The  water  is  taken 


172 


WATER-WORKS    MANUAL. 


WATER-WORKS    MANUAL.  173 

from  the  main  discharge  pipe  of  the  pumps  and  is  wasted  after 
use.  Wheels  of  this  sort  are  now  built  so  that  the  size  of  the  jet, 
and  consequently  the  power  developed,  can  be  varied  between 
wide  limits.  It  seems  to  be  pretty  clearly  demonstrated  that 
where  but  a  few  lights  are  needed,  such  an  equipment  furnishes 
them  at  a  very  low  cost. 


CHAPTER  XV.— INTAKES  AND  INTAKE  PIPES. 

Where  water  is  drawn  from  a  pond  or  river  it  is  generally  neces- 
sary to  extend  an  intake  pipe  into  the  lake  to  an  intake  of  some 
form.  The  intake  may  be  connected  directly  to  the  pump  and 
form  its  suction  main,  but  it  is  better  to  construct  a  pump  well  or 
basin  into  which  the  intake  pipe  will  discharge  by  gravity  and 
from  which  an  independent  suction  main  may  be  run  to  the 
pump.  The  location  of  the  pump  well  is  determined  mainly  by 
three  considerations.  The  first  is  the  desirability  of  having  the 
suction  main  as  short  as  possible  to  keep  down  the  friction  of  the 
water  in  passing  through  it.  The  second  is  the  necessity  of  laying 
the  suction  main  below  the  frost  line  in  the  earth  and  on  a  uni- 
form rising  grade  to  the  pump.  The  third  is  the  necessity  of  hav- 
ing the  intake  pipe  discharge  plenty  of  water  by  gravity  into  the 
well  at  all  stages  of  the  river  or  pond.  The  pipe  offers  a  certain 
amount  of  resistance  to  the  flow  of  water  and  allowance  must  be 
made  for  this.  As  a  rule  the  amount  of  trenching  necessary  to 
bring  the  intake  pipe  into  the  well  is  much  greater  than  that  re- 
cpired  to  place  the  suction  main  below  the  frost  level,  and  on  this 
account  it  is  desirable  to  place  the  well  near  the  shore.  The 
length  of  suction  main  to  reach  the  well  when  so  placed  may, 
however;  make  it  more  advantageous  to  spend  somewhat  more 
money  and  locate  the  well  nearer  the  pumping  station.  Under 
some  conditions  it  may  prove  desirable  to  build  a  basin  of  some 
size  rather  than  a  small  well,  so  as  to  have  a  supply  of  water  suffi- 
cient for  several  hours  or  a  day  of  maximum  consumption.  The 
conditions  under  which  such  a  method  of  construction  are  de- 
sirable are  so  special,  however,  as  not  to  warrant  their  discussion 
in  this  book. 

The  usual  form  of  intake  for  small  works  is  a  strong  timber  crib 
filled  with  stone  and  having  a  vertical  pipe  rising  a  short  distance 


TF.4  TER-WORKS    MANUAL.  175 

above  its  top.  The  bottom  of  the  pipe  ends  in  a  quarter  bend  or 
tee  by  which  it  is  connected  with  the  end  of  the  intake  pipe. 
Sometimes  the  intake  crib  is  not  supplied  with  a  vertical  pipe,  and 
the  water  passes  down  through  a  horizontal  grating  into  a  chamber 
containing  the  end  of  the  intake  pipe. 

Where  the  current  is  sometimes  strong  and  the  bottom  iocky, 
a  trench  should  be  blasted  for  the  intake  pipe.  If  it  is  not  laid  in 
a  trench  it  is  liable  to  be  injured,  and,  if  it  is  broken  so  as  to  be 
even  partially  stopped,  the  water-works  may  be  seriously  crippled 
for  several  days.  The  intake  itself  for  such  a  situation  is  some- 
times a  well-braced  sheet-iron  box  with  perforated  sides,  securely 
anchored  to  the  bed  rock.  The  expense  of  having  this  work  well 
done  by  a  competent  diver  is  comparatively  large,  but  fully  war- 
ranted if  the  local  conditions  render  the  usual  intake  unsafe. 
Where  the  river  carries  no  silt,  it  may  answer  to  blast  a  small  pit 
in  the  rock  bottom  and  let  the  intake  pipe  terminate  in  this,  using 
a  quarter  bend  and  a  short  pipe  extending  downward  and  per- 
forated on  the  sides  if  necessary. 

The  methods  of  laying  intakes  are  legion.  Some  of  the  most 
interesting  are  described  in  the  remainder  of  this  chapter,  and 
hints  for  other  methods  will  be  found  in  the  section  on  submerged 
pipe  of  Chapter  XVII. 

Wooden  stave  pipe  has  been  used  for  intake  pipes  on  the  Pa- 
cific Coast,  and  seems  to  be  well  suited  for  the  purpose.  The 
pipe  is  made  by  banding  together  carefully  milled  staves  of  red- 
wood, Douglas  fir  or  similar  sound,  clear  wood.  Intake  pipes 
of  such  a  type  can  be  readily  floated  into  place  and  anchored  by 
timber  cribs  built  over  them  and  sunk  by  rocks.  Care  must  be 
taken  that  no  serious  strain  comes  on  the  pipe  at  any  place,  and 
for  this  reason  each  anchorage  crib  should  be  hung  by  stout 
tackle  from  a  scow  or  pile  platform  until  it  rests  on  the  bottom. 
In  one  instance  a  wooden  gate  chamber  was  employed  with  such 
an  intake  pipe. 

A  form  of  intake  used  at  several  works  drawing  water  from 
Lake  Michigan  was  introduced,  so  far  as  the  writer  has  been  able 
to  learn,  by  Dousman  &  Sheldon,  of  Milwaukee.  It  is  a  cast-iron 
cone  with  the  intake  opening  at  the  apex.  The  intake  at  South 
Milwaukee  has  a  diameter  at  the  base  of  15  feet  and  the  exterior 
surface  is  curved  to  a  radius  of  about  G  feet.  The  metal  is  1-J 
inches  thick  and  is  pierced  near  the  bottom  to  allow  the  12-inch 


176  WATER-WORKS    MANUAL. 

intake  pipe  to  pass  through  the  side  and  connect  with  a  special 
casting  inside  the  intake.  This  rises  in  a  bell-shaped  form  at 
the  top  of  the  cone  and  is  there  covered  by  a  cast-iron  hemis- 
phere perforated  with  -J-inch  holes  1.2  inches  apart.  The  in- 
take is  held  in  place  on  the  bottom  by  riprap  dumped  over  its 
flaring  surface. 

On  account  of  the  occasional  stoppage  of  intakes  by  anchor 
ice,  the  plan  has  been  followed  in  some  cases  of  running  pipes 
from  the  main  intake  to  perforated  cylinders  or  boxes  50  feet  or 
so  away.  These  are  supposed  to  serve  as  supplementary  intakes 
in  case  the  grating  over  main  entrance  becomes  clogged  with  ice. 
The  plan  seems  to  work  successfully,  which  may  be  due  to  the 
fact  that  water  is  taken  at  points  so  far  apart  that  there  is  no 
appreciable  current  toward  any  of  them. 

Filter-crib  inlets  in  the  bottom  of  rivers  have  been  used  by 
James  II .  Harlow,  M.  Am.  Soc.  C.  E.,  at  a  number  of  places  in 
the  Pittsburg  region,  where  the  water  contains  so  much  silt  at 
times  that  special  precautions  must  be  taken  to  keep  it  out  of 
the  pipes.  A  basin  is  dug  at  some  point  in  the  bottom  where 
the  current  is  strong  enough  to  keep  the  larger  suspended  ma- 
terial from  settling.  A  timber  crib  is  then  sunk  in  this  basin 
and  covered  with  4  feet  of  stone,  gravel  and  sand  so  as  to  form 
a  filtering  material  which  will  intercept  the  silt.  It  seems  im- 
probable that  such  filtering  cribs  effect  any  marked  improvement 
in  the  chemical  or  bacteriological  character  of  the  water,  but  their 
extensive  use  along  the  Allegheny  Eiver  may  be  considered  proof 
that  their  primary  purpose,  the  prevention  of  turbidity,  is  at- 
tained. The  crib  differs  materially  from  the  older  filter  gallery 
in  having  a  much  greater  surface  and  much  less  thickness  of 
material  through  which  the  water  percolates.  Provision  is  usu- 
ally made  for  washing  them  by  reversing  the  current  through 
the  intake  pipe;  this  is  accomplished  by  putting  a  by-pass  about 
the  pumping  plant  and  allowing  water  for  the  flushing  to  flow 
backward  from  the  reservoir  or  standpipe. 

The  intake  system  of  the  water-works  of  the  Ivorydale  manu- 
facturing establishment  is  one  of  the  most  notable  instances  of 
the  filter  system  with  which  the  writer  is  acquainted.  About 
1,000,000  gallons  daily  are  drawn  from  a  muddy  stream  which 
furnishes  water  unfit  for  use  in  its  natural  condition.  Eows  of 
S-inch  oak  sheet  piling  were  driven  into  the  bed  of  the  creek 


WATER-WORKS    MANUAL.  177 

so  as  to  enclose  an  area  of  about  4,000  square  feet.  The  mud 
was  removed  from  this  area,  leaving  a  smooth  hard  clay  surface, 
on  which  was  laid  a  network  of  6-inch  drain  tiles  with  open 
joints,  which  finally  united  at  one  point  of  the  enclosure  with 
ten  lines  of  6-inch  tiles  forming  the  effluent  conduit.  The  en- 
closure was  then  covered  with  2  feet  of  broken  stone,  1  foot  of 
gravel  and  1  foot  of  sand.  While  such  an  intake  does  not  appeal 
very  strongly  to  the  engineer  in  the  light  of  present  knowledge, 
it  was  apparently  never  intended  to  act  otherwise  than  as  a 
strainer,  for  the  water  flows  through  the  effluent  pipes  into  a 
pump  well  whence  it  is  forced  t  j  an  open  sand  filter  for  real  puri- 
fication. 

The  new  intake  of  the  Salem,  Ore.,  water-works  is  another  ex- 
ample of  the  submerged  crib  type.  It  is  20  x  60  feet  in  plan  and 
divided  by  cross  timbers  into  twelve  compartments.  It  is  sunk 
in  a  sand  bar  of  the  Willamette  Eiver,  which  is  separated  by  a 
2-foot  layer  of  hard-pan  from  a  stratum  of  coarse,  water-bearing 
gravel.  The  top  and  upper  part  of  the  sides  of  the  crib  are 
sheathed  with  a  double  layer  of  2-inch  plank  which  renders  it 
probable  that  most  of  the  water  drawn  from  this  source  comes 
from  the  gravel. 

A  special  form  of  intake  used  at  the  end  of  a  24-inch  intake 
pipe  laid  in  1894  at  Burlington,  Vt,  is  a  copper  cylinder  attached 
to  the  end  of  an  upright  pipe  held  firmly  by  a  pile  of  riprap  stone 
around  it.  This  cylinder  is  considerably  greater  in  diameter  than 
the  vertical  pipe  and  perforated  on  the  top,  side  and  overhanging 
bottom.  The  bottom  is  also  fitted  with  hinged  shutters  folding 
upward,  which  are  intended  to  allow  water  to  pass  into  the  intake 
pipe  even  when  the  perforations  are  closed  by  anchor  ice. 

The  fear  of  anchor  ice  is  ever  present  during  the  winter  with 
superintendents  of  works  in  Northern  States,  and  they  have 
adopted  a  number  of  methods  of  protection  against  stoppage  of 
the  intakes.  A  frequent  and  serviceable  one  is  the  use  of  a  small 
pipe  run  through  or  alongside  the  intake  pipe  to  the  screen  at  the 
intake.  In  case  ice  clogs  the  screen  steam  is  turned  into  the  pipe 
from  the  boilers  and  the  ice  blown  away  or  melted.  Compressed 
air  has  also  been  used  for  the  same  purpose.  When  it  is  employ- 
ed, the  entrance  to  the  intake  is  a  series  of  flaps  opening  upward, 
and  so  arranged  that  in  case  their  perforations  become  clogged, 
the  compressed  air  blown  against  their  lower  surfaces  not  only 


178  WATER-WORKS    MANUAL. 

lifts  them  but  also  blows  the  ice  away  from  the  holes.  Mr.  Jo- 
soph  G.  Falcon  has  carried  the  use  of  compressed  air  still  farther 
in  a  revolving  intake  he  has  built  at  several  places.  The  water 
enters  the  intake  pipe  through  a  revolving  drum  which  is  rotated 
about  a  horizontal  axis  by  the  compressed  air  before  it  escapes. 
The  device  is  patented  and  details  of  its  construction  can  doubtj 
less  be  obtained  from  the  inventor,  whose  address  is  Evanston,  111. 

/The  most  remarkable  combined  suction  and  intake  pipe  with 
which  the  writer  is  acquainted  is  at  Auburn,  N.  Y.  It  starts 
from  deep  water  in  Owasco  ^ake  and  runs  up  hill  and  down  dale 
with  entire  disregard  of  gradients  to  a  pumping  station  9,560  feet 
distant  from  the  intake.  The  pipe  is  24  inches  in  diameter,  and 
has  numerous  valleys  and  summits,  one  of  the  latter  being  18 
feet  above  low-water  level  in  the  lake  and  one  of  the  former  a 
submerged  line  under  a  stream  near  the  pumping  station.  The 
reason  for  adopting  such  a  remarkable  profile  was  the  desire  to 
save  expensive  trenching.  No.  suction  pipe  having  such  pockets 
for  air  can  be  operated  without  assistance,  and  in  this  case  there 
is  an  air  pump  in  the  pumping  station,  connected  with  an  air 
pipe  line  running  back  7,800  feet  over  the  top  of  the  suction 
main.  The  two  are  connected  at  every  summit  and  when  the  air 
pump  runs  there  is  no  trouble  with  the  suction  main.  If  the  air 
pump  is  shut  down  for  more  than  a  couple  of  hours  or  so  trouble 
ensues.  The  writer  believes  such  a  plan  deserves  little  considera- 
tion except  in  a  few  rare  cases. 

A  form  of  intake  which  has  been  used  at  Newburgh,  N.  Y., 
Jackson,  Miss.,  and  other  places  is  designed  to  allow  the  supply  to 
be  drawn  from  different  elevations.  The  intake  pipe  is  usually 
carried  on  a  trestle  of  some  sort  to  the  place  where  the  supply  is 
taken.  There  it  ends  in  a  T  branch.  Each  side  end  of  the  branch 
is  connected  by  a  sort  of  stuffing  box  joint  with  a  half  bend. 
These  bends  are  rigidly  connected  by  flange  joints  to  the  ends  of 
another  T  branch  from  which  the  intake  pipe  proper  projects. 
This  combination  makes  a  movable  joint  about  which  the  intake 
pipe  can  be  swung  in  a  vertical  plane  by  means  of  a  rope  passing 
from  its  free  end  over  a  pulley  on  a  post  rising  from  the  trestle. 
An  illustration  of  the  Newburgh  pipe  was  printed  in  "The  En- 
gineering Becord"  of  September  2,  1893.  This  has  swinging 
arms  from  the  sides  of  a  wooden  intake  pipe."  Somewhat  similar 
joints  are  made  by  several  firms  for  sewage  tanks,  and  could 


WATER-WORKS    MANUAL.  179 

doubtless  be  employed  in  situations  where  the  movable  arm  is  not 
exposed  to  serious  strains. 

The  extension  of  the  20-inch  intake  pipe  at  Sheboygan,  Mich., 
was  an  instance  of  submerged  pipe-laying  by  means  of  a  derrick 
scow,  dredge  and  diver.  The  original  intake  pipe  ended  in  a  T 
with  a  piece  of  pipe  calked  in  so  as  to  extend  four  feet  abovTe  the 
bottom  of  the  lake.  The  water  entered  through  the  open  bell  end 
of  this  rising  pipe.  The  outer  end  of  the  T  was  plugged  with  a 
piece  of  wood  covered  with  canvas  and  held  by  iron  clamps.  The 
extension  was  20-inch  cast-iron  bell  and  spigot  pipe,  calked  to- 
gether in  sections  of  four  pipes  each,  except  the  first  and  last  sec- 
tions, which  were  shorter.  Between  each  section  was  a  ball  and 
socket  joint  of  the  Walker  type;  the  corresponding  halves  of  each 
joint  were  calked  with  lead  to  adjacent  ends  of  the  sections,  mak- 
ing them  average  50^  feet  in  length. 

The  dredge  dug  a  4-foot  trench  on  a  line  with  the  original  in- 
take pipe,  and,  to  get  close  to  the  T  without  disturbing  it,  dug  a 
trench  at  right  angles  to  the  line  of  the  pipe  as  close  as  possible  to 
the  T,  which  was  marked  by  a  buoy.  A  trench  was  also  dug  close 
to  the  T  and  diagonally  to  the  pipe  line  so  as  to  give  the  diver 
room  to  calk  the  first  joint. 

The  first  section  of  the  extension  was  21  feet  in  length,  with 
half  a  Walker  joint  at  one  end  and  a  spigot  at  the  other  for  en- 
tering the  T  of  the  original  intake.  A  scow  was  used  having  a 
flat  deck  large  enough  to  hold  three  sections  of  pipe,  derricks  and 
diving  apparatus.  Two  derricks  were  provided,  cleated  at  the 
bottom  and  guyed  to  overhang  the  edge  of  the  scow  far  enough  to 
lower  the  pipes  without  chafing  them.  The  short  first  section  was 
lowered  by  means  of  a  12-foot  oak  timber  6x8  inches  in  section, 
chained  to  the  top  of  the  pipe  and  fitted  with  a  chain  at  its  center 
for  attaching  the  falls  of  the  derrick.  This  section  was  lowered 
by  one  derrick  and  the  spigot  inserted  and  calked  into  the  T  by  a 
diver,  who  used  a  piece  of  flattened  1-inch  lead  pipe  for  a  gasket. 

Meanwhile  the  dredge  had  worked  ahead  and  on  the  following 
day  three  sections  were  laid.  These  were  lowered  from  the  scow 
by  the  two  derricks  by  means  of  two  pieces  of  oak,  12  feet  long 
and  6x8  inches  in  section,  chained  at  each  end  to  the  center  of 
each  length  of  pipe  and  provided  with  a  chain  at  the  center  of 
each  timber  for  attaching  the  derrick  tackle.  By  this  means  the 
weight  of  the  section  was  evenly  distributed  over  four  points. 


180  WATER-WORKS    MANUAL. 

Before  lowering  each  section  a  wooden  plug  was  bolted  to  the 
outer  end,  so  that  nothing  could  enter  the  pipes  until  the  plug 
was  removed  by  the  diver  when  ready  to  connect  the  next  section. 
When  in  a  correct  position  the  diver  attached  a  block  and  falls  to 
the  bolt  holes  in  the  two  halves  of  the  ball  and  socket  joint  and  the 
pipe  was  entered  by  this  means  by  the  men  from  the  deck  of  the 
scow,  the  diver  guiding  it  home  by  means  of  a  bar  running  through 
corresponding  bolt  holes  in  the  two  sections.  This  method  was 
followed  in  laying  all  the  sections. 

The  intake  pipe  ends  in  an  L  and  upright  piece  reaching  6  feet 
above  the  bottom  of  the  lake.  The  L  was  framed  in  with  timber 
so  as  to  give  it  a  broad  base  to  rest  on  in  the  bottom  of  the  trench. 
After  it  was  laid  a  T  was  placed  on  the  end  of  the  upright  piece, 
and  held  in  place  by  a  chain  running  through  it  and  fastened 
around  the  bell  of  the  L.  Over  the  two  openings  of  the  T  were 
placed  screens  of  1-inch  iron  bars  half  an  inch  thick  and  6  inches 
apart,  crossing  at  right  angles  and  riveted  together.  These  were 
held  in  place  by  a  half-inch  iron  rod  with  nuts  at  both  ends  prop- 
erly tightened,  running  through  the  center  bar  of  each  screen  and 
through  the  tee.  After  this  was  done  stones  were  placed  around 
the  L  and  upright  as  far  as  the  bottom  of  the  T. 

The  16-inch  intake  pipe  for  the  water-works  of  Geneva,  N".  Y., 
a  place  of  about  8,000  population,  runs  from  the  pump  well  about 
700  feet  to  a  point  in  Seneca  Lake  about  600  feet  from  the  shore, 
where  the  water  averages  25  feet  in  depth.  At  the 
shore  line  there  is  a  heavy  masonry  pier  built  about  the  pipe, 
and  there  are  several  ball  and  socket  joints  along  its  length. 
Where  it  rests  on  soft  bottom,  flat  plank  supports  were  attached 
below  the  bells  by  copper  wire.  The  intake  is  a  box  of  three- 
eighths-inch  wrought  iron  plates;  it  is  about  6  feet  square  and  3J 
feet  deep,  open  at  the  top  and  covered  with  a  screen  of  2xJ-inch 
iron  bars  spaced  3  inches  apart.  The  edges  are  strengthened  by 
3x3-inch  angles,  and  there  are  hooks  at  the  corners  for  raising  and 
lowering  the  intake.  The  end  of  the  intake  pipe  is  flared  out 
where  it  enters  the  intake,  presumably  to  reduce  the  loss  of  head 
due  to  the  entrance  of  the  water  into  the  pipe.  A  similar  but 
smaller  intake  is  used  at  Geneseo,  N.  Y.,  but  at  this  place  the 
outer  portion  of  the  submerged  intake  pipe  is  of  the  lap-welded 
type  rather  than  cast-iron.  Both  works  were  designed  by  J.  Nel- 
son Tubbs,  M.  Am.  Soc.  C.  E. 


WATER-WORKS    MANUAL.  181 

A  12-inch  wrought-iron  suction  pipe  about  2,000  feet  long  fitted 
with  the  Converse  lock  joint  was  laid  through  the  ice  at  Escanaba, 
Mich.,  in  1888,  under  the  direction  of  Mr.  E.  C.  Cooke.  The 
pipes  were  handled  by  three  tripod  derricks,  the  rearmost  being 
carried  to  the  front  as  fast  as  a  joint  was  made.  The  joints  were 
calked,  and  cross  pieces  placed  over  the  pipe  and  supported  on 
blocking.  Each  joint  was  hung  by  ropes  from  the  cross  piece  over 
it.  After  a  joint  was  calked,  the  ice  was  cut  away  for  a  pipe 
length,  a  man  stationed  at  each  rope,  and,  at  a  given  signal,  the 
pipe  was  lowered  a  short  distance.  When  the  entire  pipe  had 
been  placed  on  the  bottom  in  this  manner,  an  operation  requiring 
a  gang  of  twenty  men  and  costing  $200,  it  was  sunk  about  two  feet 
into  the  sand  by  forcing  out  the  material  from  below  it  by  means 
of  a  water  jet.  Three  men  were  required  to  run  the  portable 
pumping  plant  and  operate  the  jet;  the  work  lasted  twelve  days 
and  cost  about  $75. 


CHAPTEE  XVI.— THE  CLARIFICATION  AND  PURIFICA- 
TION  OF  WATER. 

Water  supplies  which  are  not  clear  are  generally  regarded  as 
unsafe  for  domestic  use,  while  those  which  are  colorless  and  free 
from  odor  are  considered  satisfactory.  This  popular  idea  is 
wrong;  the  healthfulness  of  a  supply  depends  on  the  presence  or 
absence  in  it  of  the  bacteria  of  disease.  An  examination  of  the 
source  of  the  water  will  show  if  it  is  exposed  to  dangerous  pollu- 
tion,, a  chemical  analysis  will  indicate  if  such  pollution  has  taken 
place,  and  a  bacterial  examination  will  check  certain  deductions 
from  the  chemical  analysis  and  indicate  whether  the  water  is  fit 
for  use  in  its  natural  state  or  should  be  purified.  These  investiga- 
tions may  show  that  a  limpid  stream  is  dangerous,  and  that  a 
turbid  one  will  furnish  a  satisfactory  supply  if  it  is  clarified  before 
use. 

Turbidity  and  color  in  water  are  not  the  same;  the  former  is 
due  to  the  presence  of  silt,  the  latter  to  dissolved  vegetable  matter. 
It  is  so  rarely  necessary  to  resort  to  special  means  of  removing 
color  from  water  that  a  discussion  of  the  subject  is  out  of  place 
here.  Clarification  by  one  method  or  another  is  frequently  de- 
sirable and  sometimes  absolutely  necessary,  and  its  essential  feat- 
ures deserve  careful  attention.  Failure  to  recognize  its  import- 
ance has  caused  many  mistakes  in  American  water-works  construc- 
tion in  the  past. 

The  turbidity  of  water  has  recently  been  studied  with  great 
care  by  Messrs.  George  W.  Fuller,  Allen  Hazen  and  other  special- 
ists. The  silt  which  causes  it  is  washed  into  the  streams  by 
heavy  rains,  and  sometimes  is  composed  of  particles  not  more  than 
0.00001  inch  in  greatest  diameter.  Very  muddy  water  may  con- 
tain 0.1  per  cent  of  its  weight  of  these  particles,  which  will  clog 
any  kind  of  a  filter  so  rapidly  as  to  make  the  filtration  of  the 
supply,  on  a  large  scale,  impracticable  until  it  has  been  at  least 


WATER-WORKS    MANUAL.  183 

partially  clarified.  The  turbidity  is  measured  by  determining  the 
depth  at  which  it  is  possible  to  see  the  point  of  a  platinum  wire 
thrust  down  vertically  into  the  water.  The  reciprocal  of  this 
depth  in  inches  has  been  arbitrarily  assumed  as  the  degree  of  tur- 
bidity. The  observations  should  be  made  when  there  is  good 
light,  but  the  wire  should  be  kept  shaded  if  the  sun  is  shining 
directly  on  it. 

When  turbid  water  is  allowed  to  remain  quiet,  the  heavier  por- 
tions settle  to  the  bottom  within  the  first  24  hours,  but  after  that 
period  sedimentation  proceeds  so  slowly  that  it  is  rarely  expedient 
to  provide  for  a  longer  period  of  subsidence.  The  fine  particles  of 
clay  still  remain  in  a  large  measure  suspended  in  the  water. 
While  subsidence  for  24  hours  may  reduce  the  total  amount  of 
suspended'  material  40  per  cent,  or  so,  it  rarely  has  as  much  effect 
on  the  turbidity  because  the  latter  is  due  mainly  to  the  very  fine 
particles  of  clay  "still  floating  in  the  water.  In  the  case  of  the 
Ohio  Eiver  water  at  Cincinnati,  Mr.  Fuller  found  that  the  fine 
clay  particles  remaining  afte~"  three  days  of  subsidence  settled 
very  slowly,  and  the  decrease  in  the  amount  of  suspended  material 
in  any  day  after  the  third  seldom  exceeded  5  per  cent.  Hence  the 
construction  of  large  reservoirs  solely  to  allow  subsidence  for  sev- 
eral days  is  rarely  advisable.  There  is  generally  no  need  for  them 
except  during  the  periods  of  flood,  and  it  is  usually  possible  at 
such  times  to  accomplish  their  object  by  less  expensive  means. 

The  effect  of  a  settling  reservoir  on  the  turbidity  of  water 
under  certain  important  conditions  is  pointed  out  clearly  by  Mr. 
Allen  Hazen  in  an  article  reviewed  in  "The  Engineering  Record" 
of  March  25,  1899.  He  assumed  a  reservoir  holding  24  hours' 
supply  into  which  the  water  is  pumped  constantly  at  one  end  and 
from  which  it  is  drawn  constantly  at  the  other.  The  water  is 
drawn  from  a  stream  which  has  a  catchment  area  above  the  intake 
of  such  size  and  shape  that  the  runoff  from  the  area  passes  the 
intake  in  less  than  24  hours.  Under  ordinary  conditions  the 
water  is  comparatively  clear,  and  is  unchanged  by  passing  through 
the  reservoir.  When  a  storm  occurs,  the  stream  becomes  turbid, 
and  muddy  water  is  pumped  into  the  basin,  but,  owing  to  the  time 
required  for  passing  through  it,  the  effluent  remains  clear  for 
some  hours.  There  is  a  gradual  mixing,  however,  and  long  before 
the  expiration  of  24  hours,  somewhat  muddy  water  appears  at  the 
outlet.  The  turbidity  in  streams  of  this  size  rarely  lasts  more 


184  WATER-WORKS    MANUAL. 

than  24  hours,  and  at  the  expiration  of  that  time  the  water  in  the 
reservoir  is  as  muddy  or  muddier  than  the  water  flowing  in  the 
stream.    Generally  the  improvement  in  the  stream  is  several  times 
as  rapid  as  in  the  basin.    The  only  time  the  latter  is  of  use  is  dur- 
ing the  first  of  the  flood,  and  its  value  is  then  due  mainly  to  its 
storage   capacity.     Under   the   assumed  Conditions   the   average 
quality  of  the  water  can  be  greatly  improved  by  using  the  reser- 
voir for  storage  rather  than  sedimentation.    It  should  be  kept  full 
during  clear-water  periods  and  pumping  to  it  should  be  stopped 
whenever  the  turbidity  exceeds  a  certain  limit,  and  the  supply 
drawn  from  the  reservoir  until  the  turbidity  again  falls  to  the 
usual  degree.     As  the   stream   becomes   larger  and   the   turbid 
periods  longer,  the  size  of  the  storage  reservoir  must  be  increased. 
In  case  a  reasonable  amount  of  sedimentation  does  not  clarify 
the  water  sufficiently,  it  is  necessary  to  resort  to  filtration  for  fur- 
ther treatment,  but  it  is  highly  important  to  have  as  little  silt  as 
practicable  in  the  water  applied  to  the  filters.    The  latter  continue 
the  process  of  clarification  by  acting  as  strainers,  by  the  adhesion 
of  the  suspended  material  to  the  grains  of  the  filters,  and  by  the 
sedimentation  which  occurs  in  them  on  account  of  the  slow  veloc- 
ity with  which  the  water  passes  downward.     The  last  is  particu- 
larly important  in  the  case  of  water  containing  very  fine  sus- 
pended material,  and  may  make  it  necessary  to  operate  the  filter 
at  a  much  slower  rate  for  clarification  than  is  needed  for  satisfac- 
tory bacterial  purification.    In  case  sedimentation  and  these  three 
processes  of  clarification  are  inadequate  to  accomplish  the  desired 
result,  recourse  must  be  had  to  the  use  of  a  coagulant,  which  will 
unite  the  minute  particles  of  suspended  material  into  masses  of 
sufficient  size  to  be  stopped  by  the  filter.    Sulphate  of  alumina  is 
the  coagulant  commonly  employed  for  the  purpose.     The  carbon- 
ate of  lime  dissolved  in  the  water  unites  with  it  chemically  and 
two  new  substances  result;  sulphate  of  calcium,  which  remains  in 
solution,  and  hydrate  of  aluminum,  which  has  the  form  of  little 
flakes  of  jelly.     It  is  the  latter  which  collect  the  floating  particles 
of  clay  and  carry  them  to  the  filter.     The  success  of  coagulation 
in  this  manner  depends  on  the  presence  in  the  water  of  enough 
dissolved  lime  to  change  the  sulphate  of  alumina  in  the  manner 
mentioned.     Unfortunately,  the  amount  of  dissolved  lime  is  gen- 
erally least  during  floods,  when  it  is  most  necessary,  and,  as  Mr. 
Hazen  has  shown  very  forcibly,  it  may  happen  that  serious  trouble 


WATER-WORKS    MANUAL.  185 

will  be  experienced  at  such  times,  even  with  waters  which  ordi- 
narily present  no  difficulties  in  this  respect. 

SAND  OR  ENGLISH  FILTERS. 

The  usual  purpose  of  filtration,  at  least  of  filtration  through 
large  beds  of  sand  at  low  rates,  is  not  so  much  the  clarification  as 
the  purification  of  the  water.  The  general  nature  of  the  process 
is  readily  understood.  The  raw  water  is  clarified  if  necessary  and 
then  turned  over  the  top  of  a  layer  of  sand,  which  is  supported  by 
a  bed  of  well-drained  gravel.  It  passes  through  the  sand  and  is 
clarified  in  its  course  by  the  three  causes  previously  mentioned.  A 
result  of  this  clarification  is  the  formation  of  a  layer  of  sediment 
on  the  surface  of  the  sand,  which  is  itself  a  filter  of  much  finer 
pores  than  the  original  layer  of  sand.  The  interstices  are  so  small 
that  the  bacteria  are  caught  in  them  and  the  water  is  thus  purified 
as  well  as  clarified.  Various  chemical  changes  also  take  place  in 
the  water,  which  are  not  definitely  understood.  As  the  sediment 
on  the  surface  of  the  filter  becomes  thicker  and  thicker,  the  re- 
sistance it  offers  to  the  passage  of  water  increases,  and  it  is  neces- 
sary to  increase  the  depth  of  water  over  the  sand  in  order  to  keep 
the  rate  of  filtration  uniform.  Finally  the  resistance  of  this  sur- 
face film  becomes  so  great  that  it  must  be  removed,  which  is  ac- 
complished by  skimming  off  half  an  inch  to  an  inch  of  the  top  of 
the  sand  bed.  The  sand  which  is  removed  can  be  washed  and 
used  again,  or  it  can  be  thrown  away  and  a  fresh  supply  obtained; 
generally  it  is  cheaper  to  wash  the  sand.  In  order  to  clean  the 
filter  it  is  necessary  to  throw  it  out  of  service  for  a  time,  and  it  is 
therefore  desirable  to  have  a  number  of  filter  beds,  so  that  the 
temporary  disuse  of  one  of  them  will  not  interfere  with  the  supply 
of  filtered  water  to  the  community. 

Inasmuch  as  the  efficacy  of  filtration  depends  very  largely  on 
the  character  of  the  sand  used  in  the  beds,  it  is  important  to  con- 
sider this  subject  in  detail.  The  sand  must  be  clean,  and  should 
consist  mainly  of  sharp  quartz  grains.  The  remaining  particles 
may  be  hard  silicates,  although  pure  quartz  sand  is  desirable.  Its 
physical  properties  are  commonly  classified  by  the  methods  estab- 
lished several  years  ago  by  the  specialists  of  the  Lawrence  Experi- 
ment Station  of  the  Massachusetts  State  Board  of  Health,  par- 
ticularly by  Mr.  Allen  Hazen,  whose  book  on  the  filtration  of  pub- 
lic water  supplies  should  be  purchased  by  the  water  board  of  every 


lbt>  WATER-WORKS    MANUAL. 

community  where  filtration  is  proposed  or  practiced.  The  in« 
vestigations  of  these  engineers  have  shown  that  the  value  of  any 
sand  for  filtering  depends  very  largely  on  the  smaller  particles, 
and  on  the  uniformity  of  size  of  the  grains.  The  first  relation  is 
expressed  by  stating  the  effective  size  of  the  given  sand,  which  is 
arbitrarily  assumed  to  be  the  size  of  grain  which  is  exceeded  by 
90  per  cent,  by  weight  of  all  the  particles.  The  second  relation  is 
expressed  by  stating  the  uniformity  co-efficient,  the  ratio  of  the 
size  of  the  grain  which  has  60  per  cent,  of  the  sample  finer  than 
itself  to  the  size  which  has  10  per  cent,  finer  than  itself.  The 
latter  size,  it  will  be  observed,  is  the  effective  size.  The  various 
sizes  are  determined  by  sieves,  and  are  expressed  in  millimeters,  as 
the  metric  system  of  weights  and  measures  is  now  universal  in  all 
scientific  work,  not  only  on  account  of  the  labor  it  saves  but  also 
because  it  is  the  common  system  of  scientists  of  all  nations.  A 
millimeter  is  0.03937  inch. 

The  sieves  used  for  separating  the  particles  are  made  of  brass 
wire  and  are  shaken  by  hand  or  by  an  apparatus  illustrated  in 
"The  Engineering  Record"  of  January  23,  1897.  '  Mr.  James  FL 
Fuertes  uses  a  set  of  tin  cups  fitting  end  to  end,  each  cup  having  a 
screen  soldered  in  the  bottom.  A  sample  of  sand  is  placed  in  the 
top  cup  and  the  entire  nest  shaken  by  hand.  A  series  which  has 
been  found  useful  has  approximately  2,  4,  6,  10,  20,  40.  70,  luO 
and  200  meshes  to  the  inch,  although  the  exact  number  is  of  no 
importance.  The  real  size  of  each  screen  is  determined  by  experi- 
ment. A  thousand  or  so  of  the  last  particles  to  pass  the  sieve,  ex- 
cept in  the  case  of  those  of  the  larger  meshes,  are  caught,  counted 
and  weighed.  The  total  weight  of  these  grains  divided  by  the 
total  number  gives  the  average  weight  of  a  particle.  The  specific 
gravity  of  the  sand,  which  runs  from  2.6  to  2.7  in  material  suit- 
able for  a  filter,  should  be  determined.  The  size  of  the  screen  is 
then  assumed  to  be  that  of  the  diameter  of  a  sphere  of  the  weight 
and  specific  gravity  of  the  average  of  these  particles  which  passed 
it  last.  The  volume  of  the  sphere  is  the  weight  divided  by  the 
specific  gravity,  and  the  volume  multiplied  by  1.91  gives  the  cube 
of  the  diameter.  If  the  weight  is  expressed  in  milligrams,  the 
diameter  will  be  expressed  in  millimeters.  The  size  of  each  screen 
is  determined  in  this  manner,  and  when  this  has  once  been  done 
it  is  an  easy  matter  to  find  the  effective  size  and  uniformity  co- 
efficient of  any  sand.  A  sample  is  carefully  weighed  and  passed 


WATER-WORKS    MANUAL.  187 

through  one  sieve  after  another  until  one  is  found  which  will  pass 
only  10  per  cent,  of  the  total  quantity.  The  size  of  this  sieve  is 
the  effective  size  of  the  sand.  In  the  same  way  a  sieve  should  be 
found  which  will  pass  60  per  cent,  of  the  sample.  The  ratio  of 
this  size  to  the  effective  size  is  the  uniformity  co-efficient. 

Although  these  terms  are  employed  in  a  largely  arbitrary  man- 
ner, yet  their  value  is  evident  when  a  study  is  made  of  the  utility 
of  various  sands  for  filtering  purposes.  It  has  been  determined 
for  example,  that  the  smaller  the  effective  size  of  the  sand  the 
greater  the  bacterial  efficiency  of  the  filter,  tests  at  Lawrence  giv- 
ing results  shown  in  the  accompanying  table.  While  the  size  of 
grains  is  thus  found  to  affect  the  degree  of  purification,  it  was 
learned  at  the  same  time  that  the  frequency  with  which  it  is  neces- 
sary to  scrape  a  filter  during  the  course  of  a  year  depends  upon  the 
effective  size  of  the  sand.  These  results  are  given  in  the  same 
table.  In  each  case  the  maximum  loss  of  head  before  scraping 
was  70  inches. 

The  Influence  of  Size  of  Sand  on  Filtration. 

(From  Kept.  Mass.  State  Board  of  Health,  1893  ) 

Rate  of  Filtra.  Bacterial  Total  Effluent 

Effec.         Unif.      Depth.          Gals,  per  Efficiency,  bet.  scrapings. 

Size.           Coef.          Ins.          Acre  Daily.  Per  Cent.  Gallons. 

0.09              2.1              45                1,580,000  99.978  14,000,000 

0.14              2.2              60                2,160,000  99.964  49,00  ,000 

0.20              1.6              55                2,420,000  99.990  56,000,000* 

0.26              3.7              60                4,848,000  99.901  57,000,000 

0.29              2.7              60                4,940,000  99.917  70,000,000 

0.38              3.5              60                3,800,000  99.840  79,000,000 
*  This  figure  is  taken  from  the  Report  for  1892. 

These  figures  show  that  there  is  a  limit  beyond  which  it  is  not 
practical  to  decrease  the  size  of  the  sand  grains;  this  limit  is  differ- 
ent in  filters  which  must  treat  river  water  containing  silt  and  those 
for  clear  lake  water.  The  long  experience  of  the  managers  of  the 
London  water  companies  has  led  them  to  use  sands  which,  when 
washed,  vary  in  effective  size  between  0.25  and  0.36  millimeter  and 
have  a  uniformity  co-efficient  of  1.8  to  2.4.  These  filters  are  used 
to  purify  water  which  has  considerable  turbidity  at  times,  but  is 
subject  to  sedimentation  for  several  days  before  filtration.  The 
Hamburg  filters  use  a  washed  sand  of  an  effective  size  of  about 
0.32  millimeter,  with  a  uniformity  co-efficient  of  about  2.3.  These 
are  also  used  with  river  water.  The  Mueggel  Lake  filters  of  the 
Berlin  works  use  sand  of  0.35  millimeter  effective  size,  which  has 
a  uniformity  co-efficient  of  1.8.  The  celebrated  Zurich  filters  use 


188  WATER-WORKS    MAX  UAL. 

a  sand  of  0.3  millimeter  effective  size  with  a  uniformity  co-efficient 
of  3.1,  which  is  very  high.  As  a  general  rule,  the  sand  selected  for 
a  filter  should  have  an  effective  size  between  0.2  and  0.35  milli- 
meter, and  a  uniformity  co-efficient  under  3. 

The  thickness  of  the  sand  bed  should  never  fall  below  12  inches, 
and  16  inches  is  a  much  better  limit.  The  thickness  when  new 
may  be  from  30  to  40  inches.  Experiments  made  by  the  Massa- 
chusetts State  Board  of  Health  in  1896  show  that  the  effluent  from 
thick  beds  is  better  than  that  from  thin  ones,  other  conditions  be- 
ing the  same.  It  is  customary  to  store  the  sand  scraped  from  the 
filters  from  time  to  time  until  the  depth  remaining  is  the  mini- 
mum. Then  the  sand  is  washed,  and  the  bed  brought  back  to  its 
original  level. 

It  is  essential  to  have  each  filter  bed  in  a  water-tight  basin. 
Sometimes  puddle  covered  by  a  pavement  is  used  as  lining  for 
this  purpose,  and  sometimes  concrete,  the  preference  being  for  the 
latter.  Small  filters  enable  a  better  control  to  be  exercised  over  the 
filtration,  anr1  permit  cleaning  or  renewal  without  interfering  to 
any  great  extent  with  the  supply;  they  are  also  of  decided  ad- 
vantage if  it  is  necessary  to  cover  the  niters  as  a  protection  against 
freezing.  Large  beds  are  less  expensive  to  construct  on  account 
of  the  fewer  walls  and  embankments  needed  with  them.  From 
one-half  to  one  acre  will  probably  be  found  the  limiting  sizes  of 
each  bed  under  most  conditions,  although  in  small  works  it  may  be 
desirable  to  use  beds  as  small  as  a  quarter  of  an  acre  each  in  order 
to  provide  for  the  exigences  of  cleaning  and  slower  nitration  dur- 
ing cold  weather.  If  the  filters  are  to  be  built  at  a  place  where  the 
January  temperature  is  below  the  freezing  point  it  will  probably 
prove  advisable  to  cover  them.  This  can  be  done  in  several  ways, 
but  that  adopted  for  the  beds  at  Somersworth,  N.  H.,  by  Mr.  Wil- 
liam Wheeler,  M.  Am.  Soc.  C.  E.,  and  illustrated  in  "The  Engi- 
neering Record"  of  August  27,  1898,  will  probably  prove  suitable 
for  many  places.  A  discussion  of  the  principles  on  which  such  a 
roof  should  be  designed  is  outside  the  scope  of  this  book;  they  are 
stated  concisely  and  clearly  in  Prof.  I.  0.  Baker's  "Treatise  on 
Masonry  Construction." 

The  sand  must  be  supported  on  some  coarse  material  in  order 
that  water  passing  through  it  may  run  off  as  freely  as  possible. 
Formerly,  the  support  was  a  series  of  layers  of  coarse  gravel  and 
sand,  growing  finer  with  its  distance  above  the  floor  of  the  basin. 


WATER-WORKS    MAX  UAL.  189 

It  has  been  found  by  experience  that  this  complication  of  strata 
is  an  unnecessary  expense.  It  is  probable  that  G  inches  of  coarse 
gravel  and  three  to  five  2-inch  layers  of  material  uniformly  placed 
and  decreasing  in  size  to  coarse  sand  in  the  top  layer,  will  prove 
amply  sufficient  to  support  the  bed  of  sand  and  allow  the  passage 
of  water.  Care  must  be  taken  that  the  stones  or  grains  of  each 
layer  are  fairly  uniform  in  size,  and  that  their  relative  sizes  are 
such  that  the  material  of  any  one  layer  will  not  be  driven  down 
into  that  below. 

The  gravel  contains  a  network  of  underdrains  through  which 
the  filtered  water  is  drawn  off.  Tile  drains  are  generally  employed 
for  the  lateral  branches  and  these  discharge  into  a  main  drain  with 
sides  of  dry  brickwork  and  a  cover  of  stone  slabs,  allowing  water 
to  enter  it  freely.  All  the  drains  should  be  so  arranged  that  the 
sand  has  a  uniform  thickness  at  every  part  of  the  bed.  Mr.  Hazen 
has  suggested  that  the  limiting  areas  round  tile  drains  should  be 
required  to  drain  are  as  follows:  4-inch,  290  square  feet;  6-inch, 
750  square  feet;  8-inch,  1,530  square  feet;  10-inch,  2,780  square 
feet;  12-inch,  4,400  square  feet.  Larger  drains  should  have  an 
area  at  least  1-6,000  of  the  area  drained. 

The  apparatus  for  applying  water  to  the  filter  beds  and  for 
drawing  it  off  vary  widely.  Some  means  must  be  provided  for 
regulating  the  filtration  head  so  that  the  bed  yields  a  definite 
quantity  of  water  all  the  time  it  is  in  service.  For  small  beds  the 
best  method  of  accomplishing  this  will  probably  lie  in  maintain- 
ing a  fixed  depth  of  water  over  the  sand  and  varying  the  eleva- 
tion of  discharge  of  the  filtered  water.  If  this  elevation  is  nearly 
that  of  the  water  level  over  the  bed  the  discharge  will  be  small,  and 
if  the  effluent  is  drawn  from  a  lower  point  the  quantity  will  be 
greater,  provided  the  bed  has  not  become  clogged  meanwhile.  A 
good  idea  of  this  system  of  regulation  is  furnished  by  Figures  34 
and  35,  giving  a  plan  and  details  of  a  plant  with  a  nominal  daily 
capacity  of  1,500,000  gallons  recently  built  at  Berwyn,  Pa.,  from 
the  designs  of  Mr.  J.  W.  Ledoux,  M.  Am.  Soc.  C.  E. 

There  are  three  beds  of  7,500  square  feet  each  in  a  basin  with 
rubble  masonry  side  and  partition  walls,  and  a  bottom  of  8  inches 
of  puddle  covered  by  3  inches  of  concrete.  The  sand  has  a  thick- 
ness of  30  inches,  an  effective  size  of  0.25  millimeter  and  a  uniform- 
ity co-efficient  of  1.82.  It  rests  on  gravel  6  inches  thick  and  ranging 
in  size  from  particles  the  size  of  a  pea  at  the  top  to  1^-inch  pebbles 


190 


WATER-WORKS    MANUAL. 


at  the  bottom.  The  main  drains  are  vitrified  sewer  pipes  with 
cement  joints  laid  in  a  trench  bringing  their  top  to  the  level  of 
the  bottom  of  the  basin  in  other  places.  These  drains  terminate 
in  cast-iron  pipe  running  through  the  walls.  The  laterals  are  6 
feet  apart  and  formed  of  ordinary  4-inch  tile  in  12-inch  lengths 
which  were  placed  end  to  end  without  other  joint.  They  are  also 


I 


Force  Main  to  Distributing  foservolr. 


,  12'Terra-Colta  Clean-Out 
I  ,14" C.I,  niter  Discharge. 


2j 

2E£ 

===E 

-^-,=- 

««f 

ZT  255'  Zv 

rr_trr: 

"•^_"^"^ 

NO. 

_ 

p 

_ 

^  zrrr 

"   -T  ' 
zzrfe  A/O. 

3     

- 

L  —  j 

zzzzzzr 

H- 

l-a—  

-H 

(  

/ 

FIGURE  34.— PLAN  OF  THE  BERWYN  FILTERS. 


placed  in  depressions  in  the  concrete  bottom  and  are  covered  with 
4  inches  of  gravel. 

The  water  enters  each  bed  through  an  intake  on  a  raceway  and 
a  12-inch  cast-iron  pipe  running  under  the  embankment  to  an  inlet 
chamber.  This  is  merely  a  semi-circular  wall  9  inches  thick  and 
as  high  as  the  bed  of  sand.  The  water  rises  in  it  freely  and 
mingles  freely  with  that  over  the  sand  bed  without  disturbing  the 


WATER-WORKS    MANUAL. 


191 


latter  in  any  way.  A  wire  screen  is  placed  over  the  intake  at  the 
raceway  to  keep  refuse  from  reaching  the  filter.  It  is  not  unusu- 
al to  provide  an  overflow  chamber  of  some  sort  or  else  use  a 


Bicycle  Wheel 
tor  Weir  Float  Pulley. 


Clear,  /veil  seasoned  W.P. 


Cast  Iron/ Lg. &'0"  -^ 

Section    through  Gate  House. 


?   — ^  X  ^-Brass  Index  * 

^  Brass  Wood  Screw, 
Plan  and   Elevation  of 
Gauge   Board  Index. 


Wall. 


Sectional   View  of 
Indicator     Float,and 
Attachment  to  Index. 


TbBedNoJ' 


Plan  of  Pipe  Arrangement  for 
Registering   Device 


Plan  and  Elevation 
of  Oauge  Board, 


FIGURE  35.— GATE  HOUSE  OF  THE  BERWYN  FILTERS. 

balanced  float  valve  controlling  the  flow  of  water  through  the  inlet 
pipe,  in  order  to  prevent  the  water  on  the  beds  exceeding  a  certain 
height. 

The  provision  for  maintaining  a  uniform  rate  of  percolation 


192  WATER-WORKS    MANUAL. 

through  the  filter  beds  is  described  by  Mr.  Ledoux  substantially 
as  follows:  The  regulating  apparatus  consists  of  a  brass  tube  open 
at  both  ends  and  hanging  to  a  float  which  rises  and  falls  with  the 
water  level  in  the  effluent  chamber.  The  top  of  the  tube  may  be 
considered  a  submerged  circular  orifice  or  weir,  which  is  kept  at  a 
constant  although  adjustable  distance  from  the  float.  The  float 
and  sliding  tube  are  counterweighted  as  shown  in  Figure  35.  As 
the  sand  bed  becomes  clogged  by  sediment,  the  water  level  in  the 
effluent  chamber  will  sink  and  lower  the  float  and  weir,  thus  in- 
creasing the  effective  head.  An  indicator  board  is  provided  in  the 
gate-house.  It  has  seven  indicators,  one  for  each  filter  bed,  one  for 
each  effluent  chamber  in  the  gate-house,  and  one  for  the  clear- 
water  basin.  The  difference  in  level  between  the  water  on  a  bed 
and  in  the  corresponding  effluent  chamber,  which  indicates  the  loss 
of  head,  is  shown  at  a  glance.  The  indicators  slide  in  vertical 
grooves  and  are  attached  to  No.  26  copper  wires,  which  run  over 
brass  pulleys.  Attached  to  the  other  end  of  the  wires  are  floats 
made  of  3-inch  nipples  capped  at  each  end.  These  floats  work  in 
pipes  having  half-inch  pipe  connections  with  the  water  on  the 
filter  beds,  in  the  effluent  chambers  and  in  the  clear-water  basin. 

The  cost  of  this  entire  filter  system  was  $18,536;  the  most  ex- 
pensive single  item  was  $4,420  for  2,697  tons  of  sand  from  Glouces- 
ter, N.  J.,  and  the  next  was  $2,927  for  528  yards  of  stone  masonry. 

There  are  various  methods  of  washing  sand,  those  mainly  em- 
ployed involving  the  use  of  hoppers  of  the  form  shown  in  "The 
Engineering  Record"  of  October  19,  1895,  or  drums  of  the  type 
illustrated  in  the  issue  of  the  same  paper  for  October  29,  1898.  In 
the  case  of  small  works  it  will  probably  prove  as  satisfactory  to 
place  the  sand  on  the  slightly  sloping,  watertight  bottom  of  an  en- 
closure having  a  low  weir  at  its  lowest  side,  and  wash  it  with  a  hose 
until  clear  water  runs  over  the  weir. 

MECHANICAL  FILTERS. 

So  far  in  the  discussion  of  filtration  it  has  been  assumed  that 
the  filters  were  of  the  English  type,  in  which  the  sand  is  scraped 
off  when  the  flow  through  it  falls  below  a  certain  rate.  In  recent 
years,  a  different  type  of  apparatus,  called  the  American  or  me- 
chanical filter,  has  been  developed,  and  is  rapidly  replacing  the 
English  beds  for  many  situations  in  the  estimation  of  engineers. 
Its  characteristics  are  described  so  clearly  in  Mr.  George  W.  Ful- 


WATER-WORKS    MANUAL.  193 

ler's  invaluable  report  on  the  Louisville  filtration  experiments, 
that  an  extract  from  this  volume  is  printed  here: 

"This  type  of  filters  is  the  outgrowth  of  schemes  to  purify  water 
for  industrial  and  manufacturing  purposes.  Its  development  up 
to  this  time  has  been  tentative  to  a  marked  degree,  and  has  been 
in  the  hands  of  several  competing  business  corporations.  In  1883 
it  first  attracted  the  attention  of  those  connected  with  public  water 
supplies.  At  that  time  it  consisted  essentially  of  a  large  circular 
tank  in  which  there  was  a  layer  of  sand  supported  by  a  perforated 
bottom.  Its  chief  characteristic,  other  than  small  size,  in  distinc- 
tion from  sand  filters,  was  the  fact  that  the  sand  layer  was  cleansed 
of  the  accumulated  materials  removed  from  the  river  water  by 
forcing  water  under  pressure  up  through  the  layer  of  sand.  In 
this  respect  it  resembled  the  filters  constructed  in  1856  at  Tours, 
in  France. 

"Patents  were  taken  out  in  1884  to  cover  a  modification  which 
consisted  of  the  application  of  alum,  a  salt  of  iron,  or  other  similar 
coagulating  chemical,  to  the  water  just  before  it  passed  through 
the  layer  of  sand.  The  custom  of  applying  alum  to  coagulate 
water,  in  order  to  facilitate  the  removal  of  foreign  matter,  has 
been  practiced  in  various  ways  for  many  centuries  in  different  parts 
of  the  world,  and  the  description  of  it  in  scientific  literature  began 
about  70  years  ago.  The  apparent  object  of  the  application  of 
chemicals  under  the  stated  conditions  are  understood  to  be  a  re- 
duction in  the  cost  of  treatment,  by  doing  away  with  subsidence 
basins  and  by  diminution  of  the  area  of  filtering  surface. 

"This  type  of  filter  was  first  employed  in  the  treatment  of  a  pub- 
lic water  supply  at  Somerville,  N.  J.,  in  1885.  Since  that  time 
many  towns  and  small  cities  have  adopted  systems  of  this  general 
type.  At  present  it  is  said  that  over  100  town  and  municipal 
plants  are  in  operation,  but  among  this  number  there  are  none  for 
large  cities. 

"In  the  last  ten  years  many  modifications  have  been  introduced 
by  the  several  competing  companies.  These  modifications,  more 
or  less  protected  by  patents,  relate  for  the  most  part  to  devices  for 
supporting  the  sand  layer  at  the  bottom;  the  introduction  of 
filtered  water  under  pressure  below  the  sand  filter,  to  enable  the 
filter  to  be  cleaned  by  a  reverse  flow  of  water;  and  of  agitating  de- 
vices to  stir  the  sand  during  washing,  and  thus  aid  the  cleansing 
process.  In  the  present  filters  of  the  several  companies  the  coagu- 


194  WATER-WORKS    MANUAL. 

lating  chemicals  are  applied  at  points  differently  located  with  refer- 
euce  to  the  sand  layer,,  and  with  varying  provisions  to  secure  not 
only  more  complete  coagulation  but  also  to  effect  a  removal  of  some 
suspended  matter  before  the  water  is  filtered.  To  this  general  ac- 
count of  the  American  niters  it  may  be  added  that  a  majority  of 
them  are  gravity  filters — where  the  water  flows  by  gravity  through 
a  sand  layer  placed  in  an  open  tank.  In  some  cases,  however,  pres- 
sure niters  are  used.  The  pressure  filters,  in  addition  to  customary 
devices,  consist  of  a  sand  layer  placed  in  a  closed  compartment,  so 
that  water  can  be  forced  through  the  filter  under  pressure,  thereby 
abiding,  it  is  claimed,  additional  pumping  under  some  conditions. 

"Compared  with  the  English  filters,  the  American  filters  at  pres- 
ent show  the  following  principal  differences.  1.  The  American 
filters  are  aided  by  the  application  to  the  water  of  a  coagulating 
chemical,,  which  makes  it  possible  to  filter  through  sand  at  a  much 
more  rapid  rate,  and  thereby  the  necessary  area  of  filter  is  much 
reduced.  2.  The  American  filters  are  cleaned  by  passing  a  stream 
of  water  upward  through  the  sand,  with  or  without  accompany- 
ing agitation,  rather  than  by  scraping  off  the  surface  layers,  as  in 
the  case  of  the  English  filters. 

"There  are  of  course  many  other  features  of  difference,  such,  for 
example,  as  the  strainers  at  the  bottom,  to  hold  back  the  sand  and 
at  the  same  time  furnish  an  exit  for  the  filtered  water;  but  the  two 
points  stated  above  are  the  principal  differences." 

It  is  natural  to  ask  why  the  first  distinctive  feature  of  mechani- 
cal filters,  the  use  of  a  coagulant,  is  not  adopted  with  the  English 
type  of  sand  filters.  The  answer  is  probably  to  be  found  in  the 
fact  that  such  filters  have  not  been  used  on  a  water  of  sufficient 
turbidity  to  make  them  necessary.  There  is  no  reason  why  alum 
should  not  be  so  employed,  and  the  subject  was  carefully  studied 
b}  Mr.  Fuller  in  his  investigation  of  methods  of  purifying  the  Ohio 
Eiver  water  for  use  in  Cincinnati.  This  water  contains  at  times 
such  a  large  quantity  of  fine  clay  particles  that  it  is  impracticable 
to  filter  it  through  sand  beds,  even  after  several  days'  sedimenta- 
tion. He  investigated  two  methods  of  treatment: 

1.  Applying  the  chemical  to  the  plain  subsided  water  when  its 
condition  demanded  it,  and  then  allowing  the  coagulated  portions 
in  suspension  to  subside  in  a  relatively  small  basin  interposed  be- 
tween the  plain  subsiding  reservoirs  and  the  filters. 

2.  Applying  the  chemical  to  the  river  water,  when  required,  be- 


WATER-WORKS  MANUAL.  195 

fore  the  water  entered  the  plain  subsiding  reservoirs,  and  allowing 
the  supplementary  clarification  to  take  place  in  the  main  subsiding 
reservoirs,,  thus  dispensing  with  the  small  intermediate  basin. 

The  second  plan  proved  preferable  for  economical  reasons. 
After  the  water  is  uniformly  prepared  for  filtration,  the  English 
type  of  filters  can  complete  the  clarification  and  purification  in  a 
satisfactory  manner  and  with  a  smaller  area  of  filters  than  is  con- 
ventionally considered  to  be  necessary.  The  methods  of  applying 
the  coagulant  are  much  more  satisfactory  with  mechanical  filters, 
however.,  and  in  the  carefully  prepared  estimates  of  the  total  cost 
of  filtering  the  Ohio  River  water  by  both  systems  of  filters,  the 
mechanical  plant  had  a  marked  advantage. 

The  details  of  these  American  types  of  filters  are  so  well  shown 
in  the  publications  of  the  companies  making  them  that  it  is  un- 
necessary to  describe  them.  The  mechanical  filter  has  successfully 
lived  down  the  attempts  made  to  discredit  it,  and  it  has  been  defi- 
nitely proved  able  to  filter  water  satisfactorily  when  properly 
handled  at  rates  of  over  100,000,000  gallons  per  acre  daily.  In- 
telligent management  is  essential  for  good  results.  Whether  the 
mechanical  or  sand  filter  should  be  employed  in  a  given  case,  is  to 
be  settled  by  a  careful  study  of  the  local  conditions,  cost  of  plant, 
operating  expenses  and  the  durability  of  the  various  parts. 


CHAPTEE  XVII.— THE  PIPE  SYSTEM. 

The  calculation  of  the  size  of  a  pipe  needed  to  furnish  a  certain 
quantity  of  water  under  given  conditions  is  readily  accomplished  if 
approximate  results  will  serve  the  purpose.  If  accurate  computa- 
tions are  needed,  it  is  allowable  to  indulge  in  some  complicated 
algebraical  equations  if  the  engineer's  mind  is  made  any  easier  by 
so  doing,  but  the  results  do  not  appear  much  if  any  more  reliable. 
The  writer  believes  that,  in  the  light  of  present  knowledge,  the 
pipe  computer  devised  by  Mr.  William  Cox  affords  the  readiest 
means  of  solving  the  problems  presented  by  the  flow  of  water  in 
pipes.  For  all  the  purposes  of  small  water-works,  however,  the 
following  methods  will  answer. 

If  water  flows  from  a  reservoir  through  a  straight  pipe  on  a 
uniform  grade  to  an  outlet,  the  amount  of  the  discharge  depends 
on  the  force  which  causes  the  water  to  flow.  This  force  is  meas- 
ured by  the  difference  in  elevation  between  the  water  levels  in  the 
reservoir  and  the  outlet,  which  is  called  the  total  head,  less  the 
entry  head  which  is  spent  in  forcing  the  water  into  the  end  of  the 
pipe,  less  the  friction  head  spent  in  overcoming  the  resistance  of- 
fered by  the  interior  of  the  pipe  to  the  passage  of  the  water  and  in 
the  churning  and  swirling  of  the  water  itself.  This  difference  is 
the  velocity  head,  and  is  the  height  through  which  the  water  would 
have  to  fall  freely  without  friction  for  it  to  acquire  the  velocity  it 
has  in  the  pipes.  It  is  evident  that  if  a  given  quantity  of  water 
has  to  be  taken  through  a  conduit  from  one  place  to  another,  a 
small  pipe  in  which  the  frictional  resistance  is  comparatively  great 
will  make  it  necessary  to  have  a  larger  total  head  than  a  pipe  of 
greater  diameter.  If  there  is  ample  head  then  a  small  pipe  may 
well  be  used,  but  it  often  happens  that  the  difference  in  elevation 
between  the  inlet  and  outlet  of  the  pipe  is  so  slight  that  only  a 
large  pipe  opposing  little  resistance  to  flow  can  be  used. 

The  entry  head  is  trifling  compared  with  the  friction  head,  in 
the  case  of  water-works  pipes,  and  the  problem  of  designing  a  water 


WA  TER-  WORKS  MANUAL.  197 

main  practically  hinges  on  the  friction  head.     This  may  be  esti- 
mated by  means  of  the  following  equation: 

Fric.  head  X  Diam.  =  Coef.  X  Length  X  Square  of  Velocity. 
In  this  equation  the  friction  head  is  expressed  in  feet,  the  di- 
ameter of  the  pipe  in  feet,  the  length  in  feet  and  the  velocity  in 
feet  per  second.     The  coefficients  depend  on  the  diameter  of  the 
pipes,  and  are  as  follows: 

Diam.,  Ins.  4  6  8  10  12 

Coefficient  ....     0.00038          0.00036          0.00034          0.00033          0.00033 

The   coefficient   for  any  other  diameter  can  be  quickly  calcu- 
lated from  the  formula 


Coefficient^  (o  019892+  M^?  ^64.34. 
\  Diameter  / 

The  diameter  should  be  expressed  in  feet  as  before.  The  fric- 
tion head  found  by  this  method  is  for  new  pipes.  It  becomes 
greater  the  longer  the  pipe  is  in  use,  and  Mr.  Edmund  B.  Weston, 
M.  'Am.  Soc.  C.  E.,  advises  increasing  the  amount  for  clean  pipes 
by  the  use  of  the  following  multipliers: 

Age  of  Pipes,  years...      10  15  20  25  30  35 

Multipliers   ...........  1.31          1.47          1.63          1.78          1.94          2.11 

The  use  of  the  formula  may  be  seen  by  solving  a  simple  problem, 
such  as  a  determination  of  the  smallest  size  of  pipe  to  deliver  750,- 
000  gallons  per  day  which  it  is  safe  to  lay  on  a  uniform  grade  be- 
tween points  15,000  feet  apart  and  differing  125  feet  in  elevation. 
The  maximum  natural  grade  per  1,000  feet  isl25-^15  =  8.33  feet. 
If  it  is  necessary  for  the  delivery  of  750,000  gallons  to  remain  con- 
stant for  20  years,  the  pipe  must  be  made  of  greater  present  capacitv 
in  order  to  allow  for  subsequent  tuberculation  and  clogging.  Hence, 
from  the  preceding  table  of  multipliers,  the  friction  head  used  in 
making  the  computations  must  be  1.63  times  that  for  clean  pipes. 
A  discharge  of  750,000  gallons  in  24  hours  is  equivalent  to  521 
gallons  per  minute.  An  inspection  of  Figure  36  shows  that  a 
6-inch  pipe,  even  when  new,  offers  too  much  friction  to  permit  of 
its  use  under  the  circumstances.  With  an  8-inch  pipe,  the  friction 
head  per  1,000  feet  of  clean  pipe  is  seen  to  be  about  5.85  feet.  If 
this  is  increased  by  using  the  multiplier  1.63,  the  resulting  product 
is  9.53  feet.  Inasmuch  as  the  natural  grade  between  the  ends  of 
the  pipe  is  only  8.33  feet  it  is  evident  that  the  8-inch  pipe  will 
probably  prove  of  insufficient  capacity  to  deliver  the  needed  vol- 
ume of  water  before  the  end  of  the  20-year  period.  The  friction 


WA  TER-  WORKS  MAX  UA  L, 


1600 


1500 


100 


3  4  5  <o  7  8 

Velocity  -  Feet  per  Second  . 

FIGURE  36.    DISCHARGE  OF  PIPES  l,(M)  FEET  LONG. 


WATER-WORKS  MANUAL.  199 

head  of  a  new  10-inch  pipe  discharging  521  gallons  per  minute 
is  about  1.84  feet,  and  when  the  main  has  been  in  service  20  years 
it  is  fair  to  assume  it  will  not  be  more  than  1.84X1-63  =  3  feet. 
As  the  available  head  is  8.33  feet,  this  10-inch  pipe  will  discharge 
more  water  than  is  wanted.  It  will  not  cost  much  more  than 
one  8  inches  in  diameter,  however,  and  will  deliver  the  water 
under  a  good  head  at  the  outlet  end  of  the  pipe,  which  is  fre- 
quently an  important  matter. 

It  rarely  happens  that  there  is  a  uniform  slope  of  the  ground 
from  one  end  of  the  pipe  to  the  other,  and  on  this  account  it  is 
necessary  to  investigate  a  little  more  carefully  what  may  take 
place  if  the  profile  of  the  main  is  wavy.  In  Figure  37  A  repre- 
sents the  reservoir  from  which  water  is  taken,  and  B  the  basin 
into  which  it  is  discharged.  There  is  an  easy  slope  from  A  two- 
thirds  of  the  distance  toward  B,  and  then  the  ground  falls  away 
more  rapidly.  If  a  pipe  of  uniform  diameter  is  laid  a  few  feet 
below  the  surface,  it  will  not  discharge  the  amount  of  water 
which  might  be  expected  to  pass  through  a  main  of  that  size  run- 
ning between  points  of  the  given  difference  in  elevation. 

The  explanation  is  to  be  sought  in  the  presence  of  the  vertical 
bend  at  C.  Here  the  grade  of  the  two  portions  of  the  pipe 
changes.  The  result  may  be  understood  most  easily  from  the  pre- 
ceding formula  for  friction  head  by  substituting  "slope"  for 
"head"  divided  by  "length,"  and  for  "velocity"  the  "discharge" 
divided  by  the  "area"  of  the  pipe.  The  formula  thus  becomes: 
Quantity=Area  V(Diam.  x  Slope-^Coef.) 

It  is  evident  from  this  equation  that  with  a  pipe  of  constant 
diameter  the  part  which  slopes  the  more  will  have  a  greater  carry- 
ing capacity,  other  things  being  equal.  In  this  particular  in- 
stance shown  in  Figure  37,  the  slope  from  A  to  C,  is  I-i-M,  and 
that  from  C  to  B  is  (H— I)-r-X.  The  section  C  B  of  the  pipe 
will  be  but  partly  full  and  the  section  A  C  will  deliver  only  the 
amount  of  water  which  is  due  to  the  difference  in  elevation  I. 
Since  the  section  C  B  acts  merely  as  a  trough,  it  may  better  be 
made  of  smaller  diameter;  in  other  words,  the  two  sections  should 
be  calculated  independently,  by  means  of  the  formula  just  given, 
to  discharge  the  desired  quantity  of  water. 

It  is  now  easy  to  understand  what  is  meant  by  the  term  hydrau- 
lic gradient.  In  Figure  38,  A  is  the  source  of  the  supply  and  B  is 
the  point  of  discharge.  At  C  there  is  a  ridge  of  land  projecting 


200 


WATER-WORKS  MANUAL. 


above  the  straight  line  drawn  between  the  water  levels  at  the  ends 
of  the  pipe,  and  at  this  point  the  pipe  rises  above  the  straight 
line.  From  what  has  already  been  said  it  follows  that  if  there 
were  two  pipe  lines  of  the  same  diameter  from  A  to  C,  one  follow- 
ing the  profile  of  the  ground  and  the  other  laid  along  the  straight 
line,  the  former  would  not  discharge  as  much  as  the  latter.  The 
straight  line  is  called  the  hydraulic  gradient,  and  no  pipe  line  of 
uniform  diameter  should  rise  above  it.  In,  case  it  is  impracticable 
to  keep  below  it,  the  main  should  be  regarded  as  a  succession  of 
pipe  lines  and  each  of  these  calculated,  independently  of  the 
others,  to  discharge  the  desired  quantity  of  water.  The  frequent- 
ly made  statement  that  a  pipe  should  not  rise  above  the  hydraulic 
gradient  is  ridiculous  unless  restricted  to  the  case  of  a  main  of 
uniform  diameter  from  end  to  end.  The  importance  of  obtaining 
a  fair  profile  of  the  country  between  the  source  of  a  water  supply 
and  the  point  of  its  discharge  is  evident  from  this  brief  discussion ; 


FIGURE  37. 


FIGURE  38. 


without  such  a  profile  it  is  impracticable  to  ascertain  whether  the 
main  is  above  or  below  the  hydraulic  gradient. 

In  case  the  water  must  be  pumped  from  a  lower  to  a  higher 
elevation,  precisely  the  same  method  of  reasoning  must  be  fol- 
lowed. There  is  the  head  due  to  the  difference  in  elevation  be- 
tween the  pumping  station  and  the  point  of  delivery,  and  the 
head  due  to  the  friction  of  the  force  main;  the  sum  of  the  two 
is  the  head  against  which  the  pump  operates.  The  friction  head 
is  calculated  precisely  as  in  the  case  of  a  gravity  main,  and  is  less 
in  a  large  than  a  small  pipe.  The  force  main,,  if  of  small  di- 
ameter,  requires  more  powerful  pumping  machinery  than  is  the 
case  when  the  diameter  is  larger.  The  power  of  the  pump  and 
the  diameter  of  the  force  main  should,  therefore,  be  determined 
together.  The  cost  and  life  of  pipes  of  different  sizes  must  be 
compared  with  the  cost,  operating  expenses  and  life  of  pumping 
plants  of  powers  corresponding  to  the  different  pipes.  The  set  of 
corresponding  figures  which  has  the  smallest  sum  is  the  one  to 


WATER-WORKS  MANUAL.  201 

be  selected.  A  complete  analysis  of  such  a  problem  in  connection 
with  works  of  larger  capacity  than  those  discussed  in  this  book 
will  be  found  in  "The  Engineering  Record"  of  February  19,  1898. 

It  has  been  assumed  so  far  in  this  chapter  that  the  problem  is 
to  compute  the  size  of  a  pipe  of  given  length  to  discharge  a  cer- 
tain quantity  of  water.  It  is  often  desirable  to  determine  how 
much  water  a  pipe  already  laid  may  be  expected  to  yield.  In  this 
case  the  first  thing  to  do  it  to  determine  whether  the  pipe  rises 
above  the  hydraulic  gradient  at  any  place;  if  it  does  not  the  total 
length  and  fall  of  the  pipe  may  be  used  in  estimating  the  dis- 
charge, and  if  it  does  the  section  of  pipe  having  the  flattest  grade 
will  be  the  one  to  employ  in  making  the  computations.  Express 
this  slope  in  feet  fall  per  1,000  feet  of  distance.  Multiply  the  co- 
efficient for  new  pipe  of  the  given  diameter  by  the  multiplier 
corresponding  to  the  number  of  years  the  pipe  has  been  in  ser- 
vice. Then,  having  the  area,  diameter  and  slope  of  the  pipe,  com- 
pute the  quantity  of  water  it  will  discharge. 

If  the  main  is  a  succession  of  pipes  of  different  diameters,  the 
total  friction  for  a  given  rate  of  discharge  is  found  by  adding 
together  the  friction  heads  in  each  section.  If  the  problem  is  to 
find  the  discharge  of  such  a  compound  main,  having  given  the 
total  head,  and  length  and  head  of  each  section,  it  is  necessary  to 
resort  to  a  roundabout  method  of  figuring.  Assume  some  dis- 
charge, and  then  compute  what  the  total  friction  head  would  be  in 
the  given  pipe  when  delivering  such  an  amount  of  water.  Then 
divide  the  really  available  head  by  this  calculated  head,  and  then 
multiply  the  assumed  discharge  by  the  square  root  of  the  quotient 
to  obtain  the  actual  discharge.  The  calculation  can  be  made  on 
the  slide  rule  with  a  single  setting,  and  the  result  will  be  sufficient- 
ly accurate  for  practical  purposes  if  there  is  not  much  difference 
between  the  assumed  and  final  discharge.  If  there  is  much  differ- 
ence it  may  be  well  to  use  the  final  discharge  of  the  first  computa- 
tion as  the  assumed  discharge  of  a  second.  These  and  many  other 
problems  are  explained  clearly  in  Mr.  Freeman  C.  Coffin's 
"Graphical  Solution  of  Hydraulic  Problems/'  an  invaluable  book 
to  all  engineers  engaged  in  hydraulic  work. 

There  remains  for  consideration  the  problem  of  a  complex 
main,  Figure  39,  in  which  the  water  reaches  a  given  point,  E,  by 
two  routes,  one  directly  along  ABE  and  one  along  A  B  C  D,  a 
problem  given  in  Mr.  Coffin's  book.  It  is  desired  to  determine 


203  WATER- WORKS  MAMJAL. 

the  loss  of  head  between  A  and  E  due  to  a  draft  of  1,000  gallons 
a  minute  at  E.  The  loss  from  A  to  B  will  be  6.7  feet  by  Figure 
36.  From  B  the  flow  divides.  It  is  self-evident  from  the  con- 
ditions that  the  loss  of  head  along  B  E  is  the  same  as  that  along 
K  C  D  E,  otherwise  there  would  be  two  pressures  at  E,,  which  is 
impossible.  It  is  necessary  to  assume  some  loss,  and  as  it  is  de- 
sirable to  make  as  close  a  guess  to  the  truth  as  possible,  it  will  be 
well  to  refer  again  to  Figure  39.  If  three-fourths  of  the  water  went 
by  the  line  B  E,  it  is  evident  from  Figure  36  that  the  friction  head 
would  be  about  7  2-3  feet,  while  the  friction  head  in  B  C  D  E  for 
the  remaining  fourth  of  the  flow  would  be  about  5  1-3  feet.  As  an 
assumption  of  6  feet  is,  therefore,  probably  somewhere  near  the 
truth,  it  will  be  employed  in  computing  the  discharge  through  the 
two  pipes,  which  will  be  assumed  to  be  new.  A  loss  of  head  of  6  feet 
on  2,000  feet  of  10-inch  pipe  corresponds,  according  to  Figure  36, 
to  a  discharge  of  about  660  gallons,  and  an  equal  loss  of  head 
along  4,000  feet  of  8-inch  pipe  corresponds  to  a  discharge  of  about 

A  2500 '-12  "Pipe.  B 2000 '-10 'Pipe. 


1000' -8"  Pipe. 
FIGURE  39. 


2000'-  8"  Pipe. 

265  gallons.  The  sum  is  925  gallons.  It  is  now  necessary  to 
divide  the  desired  discharge  by  that  calculated  for  the  assumed 
friction  head,  and  multiply  the  square  of  the  quotient  by  the 
assumed  friction  head.  Hence, 

6  (!,'  00  -*-  925) 2  =  70=  Friction  head. 

This  head  added  to  6.7  feet  from  A  to  B  gives  13.7  feet  as  the 
total  head  required  to  deliver  1,000  gallons  of  water  from  A  to  E 
o\er  the  complex  main.  As  a  matter  of  fact,  this  result  is  prob- 
ably about  0.7  foot  too  small,  but  to  obtain  more  accurate  results  it 
will  be  necessary  to  refer  to  the  tables  and  diagrams  given  in  Mr. 
Coffin's  book,  or  indulge  in  some  elaborate  calculations.  The 
method  outlined  will  answer,  however,  to  give  the  approximate 
figures  generally  desired. 

The  method  of  laying  pipes  and  conducting  other  construction 
work  connected  with  a  water  plant,  is  described  so  fully  in  the  ex- 
cellent book  by  Mr.  William  R.  Billings  entitled  "Some  Details 


WATKR-WORKS  MAX  UAL.  20  3 

of  Water- Works'  Construction,"  published  by  "The  Engineering 
Record"  at  two  dollars,  that  it  is  unnecessary  to  devote  space  to 
the  subject  here. 

DATA   CONCERNING   PIPE  AND  ACCESSORIES. 

In  the  preceding  portions  of  this  chapter  it  has  been  assumed 
that  cast-iron  pipes  were  used.  As  a  matter  of  fact  riveted  pipe 
has  been  employed  to  a  considerable  extent  for  small  works  in 
some  States  where  the  freight  charges  for  cast-iron  pipe  have  been 
so  high  as  to  prevent  its  use.  The  common  spiral  riveted  pipe, 
manufactured  for  regular  commercial  sale,  is  generally  assumed 
to  have  a  friction  loss  15  to  20  per  cent,  greater  than  that  of  good 
cast-iron  pipe  of  the  same  diameter,  at  least,  in  the  small  sizes. 
Riveted  pipe  of  special  construction,  such  as  that  used  by  Mr.  A. 
L.  Adams  for  a  14-inch  and  16-inch  conduit  for  the  Astoria,  Ore., 
water-works,  does  not  offer  so  much  resistance  to  flow. 

The  steel  of  this  conduit  was  required  to  have  an  ultimate 
strength  of  58,000  to  65,000  pounds,  an  elastic  limit  of  30,000 
pounds,  25  per  cent,  elongation  in  8  inches,  and  be  able  to  with- 
stand, without  fracture,  being  bent  cold  and  hammered  flat.  The 
sheets  came  in  4-foot  lengths,  and  were  made  up  in  alternate  large 
and  small  courses,  the  last,  a  small  one,  being  made  slightly  conical 
and  expanded  to  the  diameter  of  a  large  course  at  the  end  of  the 
pipe.  Straight  seams  were  double  riveted  and  round  seams 
single  riveted,  the  holes  being  punched  from  the  sides  coming  to- 
gether in  the  lap.  The  pipe  was  required  to  be  tight  before  dip- 
ping and  every  length  was  tested  in  that  condition.  Drops  of 
water  were  not  regarded  as  leakage.  The  pipes  which  passed  the 
test  were  coated  with  hot  asphalt  by  dipping  them  in  tanks  of  this 
material.  The  joints  were  made  by  means  of  sleeves  of  f-inch 
welded  iron  6  inches  wide,  with  a  lead  space  of  about  f-inch.  A 
reinforcing  thimble  of  No.  8  steel  8  inches  in  width  was  inserted 
half  its  width  at  the  shop  and  riveted  in  one  end  of  each  pipe. 
The  crack  at  the  junction  of  the  two  pipe  ends  was  filled  with  oak- 
um while  the  annular  space  was  filled  with  lead  only.  A  further 
account  of  this  pipe  will  be  found  in  the  "Transactions"  of  the 
American  Society  of  Civil  Engineers,  Volume  xxxvi. 

Riveted  pipe  are  often  made  slightly  conical,  the  small  end  of 
one  length  fitting  into  the  large  end  of  the  next.  The  large  end 
is  laid  down  hill,  the  pipes  are  driven  together  by  wood  mauls, 
and  when  the  main  is  finished  fine  dirt  or  clay  is  thrown  into  the 


204  WATER-WORKS  MANUAL. 

upper  end.  This  is  washed  into  the  joints  and  makes  them  water- 
tight. 

Wood  stave  pipe  is  also  coming  into  extensive  use  in  the  West. 
It  is  made  by  banding  together  carefully  milled  staves,  and  the  re- 
lation between  the  size  and  spacing  of  the  bands,  the  pressure  to 
be  sustained,  the  thickness  of  the  wood  and  other  factors  is  a 
subject  far  too  complicated  for  discussion  in  this  place.  The 
principles  governing  these  matters  were  explained  at  length  in 
"The  Engineering  Record"  of  October  8,  1898.  The  friction  loss 
in  these  pipes  is  believed  to  be  somewhat  less  than  in  cast-iron 
pipes.  The  Wyckoff  wood  pipe,  which  has  been  used  in  a  number 
of  works,  is  made  from  creosoted  staves  held  by  a  spiral  steel 
band,  and  has  given  good  satisfaction  wherever  it  has  been  used, 
so  far  as  the  writer  has  been  able  to  learn. 

The  cast-iron  pipe  for  water-works  should  be  cast  vertically 
with  the  bell  down  in  order  to  give  every  possible  advantage  to 
this  end.  It  is  customary  to  require  the  metal  to  be  free  from 
cinder  iron  or  other  inferior  admixtures,  and  to  be  remelted  in  a 
cupola  or  air  furnace  before  the  cast.  It  ought  to  have  an  even 
grain  and  be  drilled  and  cut  satisfactorily.  Specimen  bars  of  a 
good  metal  for  the  purpose,  26  inches  long,  2  inches  wide  and  1 
inch  thick,  should  sustain  a  load  of  1,900  pounds  at  their  center 
when  placed  flatwise  on  supports  24  inches  apart;  the  deflection 
should  be  not  less  than  0.3  inch  when  the  bars  are  broken.  The 
tensile  strength  of  the  metal  should  not  be  less  than  16,000 
pounds.  The  pipe  should  not  be  taken  from  the  flasks  until  suf- 
ficient time  has  passed  to  prevent  unequal  contraction  of  the  metal 
on  account  of  its  premature  exposure  to  the  air.  All  pipes  and 
special  castings  should  be  smooth,  free  from  lumps,  scales,  blisters, 
sand  holes  and  other  imperfections.  When  the  pipe  has  been 
thoroughly  cleaned  it  should  be  inspected  to  see. that  the  axis  is 
straight,  -the  metal  sound  and  of  uniform  thickness,  and  the  hubs 
and  spigots  of  proper  shape.  It  should  then  be  heated  to  about  300 
degrees  Fahrenheit  and  dipped  for  at  least  5  minutes  in  a  bath 
of  the  material  known  as  the  Dr.  R.  Angus  Smith  pipe  coating. 
After  it  has  been  removed  from  the  bath  and  cooled  it  should 
then  be  subjected  to  a  hydrostatic  pressure  of  150  to  300  pounds, 
according  to  its  proposed  use,  and  tapped  with  a  light  hammer  to 
see  that  it  is  sound  and  perfect  when  under  such  a  pressure.  The 
inspection  of  the  pipe  at  the  foundry  is  usually  done  by  an  in- 


WATER-WORKS  MANUAL.  205 

spection  company,  of  which  several  have  cards  in  "The  Engineer- 
ing Record.'' 

For  small  plants  it  is  entirely  unnecessary  to  require  the  manu- 
facturer to  cast  special  cast  numbers  and  similar  lettering  on  the 
pipe;  sufficient  letters  to  identify  the  foundry  are  all  that  are  need- 
ed, for  if  the  pipe  proves  to  be  poor  when  it  is  delivered  it  is  just 
as  easy  to  send  it  back  if  it  bears  only  the  trade  mark  of  the 
foundry  as  if  it  is  decorated  with  the  names  of  all  the  town  offi- 
cials. The  form  of  the  spigots  and  hubs  should  be  that  generally 
adopted  by  the  large  cities  in  the  vicinity.  Some  engineers  have 
a  sort  of  mania  for  devising  special  forms,  which  only  make  un- 
necessary trouble  for  the  foundrymen;  there  are  probably  a  dozen 
or  more  equally  good  ones  to  select  from  already,  and  many 
more  which  should  never  have  "gone  farther  than  the  drafting 
board. 

The  greatest  water-works  system  in  course  of  construction  while 
this  chapter  is  being  written  is  the  Metropolitan  wrorks  of  Massa- 
chusetts, for  the  supply  of  the  Boston  district  of  that  common- 
wealth. The  thickness  of  the  pipes  for  those  works  is  calculated 

by  the  following  formula: 

(p  +  q)  r 

t  = +  0.25. 

3300 

In  this  expression  t  is  the  thickness  of  the  shell  of  the  pipe  in 
inches,  p  the  static  pressure  in  pounds  per  square  inch,  q  the  pres- 


b 

"\H  '     *" 

c?^       t        ,*\  & 

0.*25 

te 

K^JtfHSH            I      ^             ^ 

^^\ 

1 

i     11 

i       id__J 

<  —  .  d  ^  -— 

12'           H 

FIGURE  40.— METROPOLITAN  PIPE  JOINT. 

sure  in  pounds  allowed  for  water  ram,  and  r  the  internal  radius  of 
the  pipe  in  inches.  The  denominator  3,300  is  one-fifth  of  the 
assumed  tensile  strength  of  cast-iron,  16,500  pounds  per  square 
inch.  The  value  of  q  for  pipes  of  10  inches  diameter  or  less  is 
assumed  to  be  120,  110  for  12  or  14-inch  pipes,  100  for  16-inch 
and  a  gradually  decreasing  number  as  the  size  increases.  Designs 
were  made  for  five  classes  of  pipes;  Class  A  for  pressures  up  to  50 


206  WA TER-  WORKS  MA N UAL. 

pounds  per  square  inch,  Class  B  up  to  65  pounds,  Class  C  up  to  87 
pounds,  Class  D  up  to  109  pounds  and  Class  E  up  to  130  pounds. 
In  the  accompanying  table  of  weights  the  iron  is  assumed  to 
weigh  0.2604  pound  per  cubic  inch,  and  the  lead  joints  to  be 
2  inches  deep  for  pipes  of  14  inches  diameter  and  less  and  2£ 
inches  for  larger  sizes. 

Weights  of  Straight  Pipes,  Metropolitan  Water-Works.  All  dimen- 
sions are  in  feet  and  refer  to  Figure  40.  The  weight  of  the  pipe  is  in 
pounds  per  foot  and  also  per  length,  and  the  weight  of  the  lead  is  for 
a  single  joint. 

£> 

Dimensions  in  Inches.  Weight  in  Pounds. 


4 

D 

1 

a 

SO 

b 
1  30 

c 

0  65 

'd 
3  00 

t 
0  40 

3 
0  40 

Pipe 
Lengtt 
230 

Per 

L.  Foot. 
17  3 

Lead 
Joint. 

7  00 

4 

E  

1. 

50 

1.30 

0  65 

3  00 

0  45 

0.40 

255 

19.7 

7.00 

fi 

D  . 

.  .1 

50 

1  40 

0  70 

3  00 

0  46 

0  40 

380 

29  2 

9.75 

C 

E 

1 

50 

1  40 

0  70 

o  00 

0  50 

0  40 

415 

31  9 

9  75 

8 

D  

1. 

50 

1.50 

0.75 

3.50 

0.52 

0.40 

565 

43.5 

12.50 

8 

E  . 

1 

50 

1  50 

0  75 

3  50 

0  55 

0  40 

600 

46  2 

12  50 

10 

D 

1 

50 

1  50 

0  75 

3  50 

0  60 

0  40 

800 

62  4 

15  25 

10 
I9 

E  ... 
B  .  .  . 

1. 

1 

50 
50 

1.50 
1  60 

0.75 
0  80 

3.50 
3  50 

0.63 
0  57 

0.40 
0  40 

840 
910 

65.7 
70  3 

15.25 
17  75 

I9 

c 

1 

50 

1  60 

0  80 

3  50 

0  61 

0  40 

970 

75  5 

17  75 

1? 

D  ... 

1 

50 

1.60 

0  80 

3.50 

0  65 

0  40 

1  030 

80.7 

18.00 

I9 

E 

.  .  .  .1 

50 

1  60 

0  80 

3  50 

0  69 

0  40 

1  095 

86  0 

18  00 

14 

B 

1 

50 

1  70 

0  85 

3  50 

0  61 

0  40 

1  130 

87  5 

20  50 

14 

C 

1 

50 

1  70 

0  85 

3  50 

0  65 

0  40 

1  200 

i.3.5 

20.50 

14 

D 

.  .  .  1 

50 

1  70 

0  85 

3  50 

0  70 

0  40 

1  290 

101  0 

20  75 

14 

E 

1 

SO 

1  70 

0  85 

3  50 

0  75 

0  40 

1  380 

108  6 

20  75 

Ifi 

B 

1 

75 

1  80 

0  90 

4  00 

0  65 

0  50 

1  380 

106  2 

31  00 

16 

c 

.  .  .  1 

75 

1  80 

0  90 

4  00 

0  70 

0  50 

1  485 

114  8 

31  00 

16 

D 

1 

7S 

1  80 

0  90 

4  00 

0  75 

0  50 

1  590 

123  3 

31  50 

IP 

E  . 

.  .1 

75 

1.80 

0.90 

4.00 

0.81 

0.50 

1.715 

133.7 

31.50 

Table  of  Weights  in  Pounds  of  Special  Castings,  Metropolitan  Water 
Board . 

Diam.,  Ins 4            6            8  10          12          14          16 

%    Bends    80        125         185  265        340        455         680 

Vs  Bends .60        100        135  185        240        345        440 

1-16  Bends    55          85        120  165        210        345         440 

Sleeves   45          67        100  120        170        220        275 

Caps    25          40          60  80        105         140        240 

Offsets 90        175        255  365        490        635 

Three-Way  Branches. — Two  Bells. 

Size,  Ins 4x4     6x4     6x6       8x4       8x6  8x810x410x6     10x810x10 

Weight   120     160     190       215        245  270      285     315       345      380 

Size,  Ins 12x4  12x6  12x8  12x10  12x12  14x4  14x6  14x8  14x10  14x12 

Weight  355     390     420      460       525  435     475     510       550      615 

Size,   Ins 14x14     16x4     16x6     16x8  16x10     16x12     16x14     16x16 

Weight 665       545       580       620  665         730         780         870 

In  these  two-bell  single  branches  the  offset  and  one  end  of  the 


WATER  WORKS  MANUAL.  207 

direct  main  have  bells  and  the  other  end  has  a  spigot.  Such  spec- 
ials often  save  cutting  pipe,  but  as  more  or  less  cutting  must 
occur  under  any  conditions  the  three-bell  branches  enable  odd 
pieces  to  be  used,  and,  in  fact,  are  preferred  by  most  superin- 
tendents for  general  use.  Except  in  the  4,  6  and  8-inch  sizes 
they  weigh  from  2J  to  4|  per  cent,  less  than  the  two-bell 
branches;  the  small  sizes  weigh  about  3  per  cent,  more  than  the 
all-bell  castings. 

Four-Way  Branches. — Three  Bells. 

Size,  Ins 4x4    6x4     6x6     8x4     8x6    8x8    10x4    10x6    10x8 

Weight 155     200     245     250     300     345      320       370      415 

Size,  Ins...  10x10  12x4  12x6  12x8  12x10  12x12  14x4  14x6  14x8 
Weight....  480  395  440  490  550  665  475  525  575 
Size,  Ins..  14x10  14x12  14x14  16x4  16x6  16x8  16x10  16x12  16x14  16x16 
Weight  ...  640  755  835  580  630  685  750  865  945  1100 

There  are  the  same  differences  between  the  all-bell  and  three- 
bell  double  branches  as  were  mentioned  in  the  case  of  the  single 
branches. 

Weight  of  Reducers. 

Size,  Ins 6  to  4      8  to  6     10  to  6     10  to  8  12  to  6    12  to  8  12  to  10 

Weight  75            115          165          185  205          225          250 

Size,  Ins 14  to  10  16  to  10            16  to  12 

Weight   ^60  300                   330 

It  is  of  course  out  of  the  question  for  a  foundryman  to  produce 
castings  of  just  these  weights  and  some  allowance  should  be  made 
for  deviations  from  the  standard  weights  prescribed.  It  is  a  very 
poor  policy  to  be  unnecessarily  rigid  in  the  pipe  for  small  water- 
works. A  variation  of  5  per  cent,  under  standard  weight  may 
well  be  allowed  and  any  reasonable  excess  of  weight  should  be  per- 
mitted, with  the  understanding  that  no  charge  should  be  made 
against  the  city  for  weights  exceeding  4  per  cent,  of  the  standard. 
The  weight  of  each  pipe  should  be  determined  independently  and 
marked  on  it  in  plain  letters. 

In  estimating  the  amount  of  pipe  needed  for  any  work  it  may 
be  necessary  to  take  into  calculation  the  slope  of  the  ground; 
for  example,  on  a  hill  rising  at  the  rate  of  one  on  seven,  the  hor- 
izontal distance  determined  by  surveys  should  be  increased  about 
one  per  cent,  in  order  to  obtain  the  true  length  of  the  pipe 
line.  The  cost  of  pipe  varies  widely,  according  to  trade  condi- 
tions; during  the  civil  war  it  was  so  high  that  cement-lined  sheet- 
iron  pipe  was  much  cheaper  and  obtained  a  strong  hold  on  the  fa- 
vor of  water-works  designers  and  officials  in  the  East. 

The  cost  of  laying  the  pipe  varies  widely,  as  is  but  natural  in 


'208 


WA  TER-  WORKS  MA  N  UA  L. 


view  of  the  range  of  conditions  under  which  the  work  is  done. 
The  figures  in  the  accompanying  table  for  work  in  Boston  afford 
a  rough  guide  for  estimates  for  the  best  grade  of  work  under  care- 
ful supervision.  These  figures  are  for  lead  at  4  cents  a  pound 
and  labor  at  $2  a  day.  Gates  and  hydrants  for  pipes  4  to  12  inches 
in  diameter,  inclusive,  cost  about  15  cents  per  foot  of  main  extra, 
under  the  conditions  of  that  city. 


Pipe. 
4  Ins..  3  cts. 


Cost  of  Pipe  Laying  in  Boston. 

Tools. 

Lead.          Cartage.          Gaskets.    Miscellaneous.    Labor. 
2  cts.  5  cts.  30  cts. 


10 


16 


4 
5 

7 
8 

11 


2  cts. 
3 

4 
5 
6 
7 


6 
7 
8 

10 
15 


35 
40 
45 
50 
60 


These  figures  are  higher  than  those  given  for  the  same  city  in 
Mr.  Billings'  book,  but  represent  the  present  condition  more 
accurately. 

A  uniform  rule  should  be  adopted  for  locating  the  stop  valves 
on  the  street  mains  so  they  can  be  found  quickly.  It  will  prob- 
ably prove  most  satisfactory  to  place  them  a  few  feet  back  from 
the  building  line  and  thus  just  off  the  street  intersection,  as  the 
roadway  at  the  intersection  is  worn  more  rapidly  than  elsewhere 
and  the  tops  of  the  cast-iron  boxes  reaching  up  to  the  surface  of 
the  street  to  furnish  access  to  the  valves,  project  in  an  unsightly 
and  inconvenient  manner.  Enough  valves  should  be  used  so  that 
the  breakage  of  a  pipe  will  cause  inconvenience  to  the  smallest 
number  of  people  possible;  it  may  even  be  advisable  to  lay  other- 
wise unnecessary  short  pipes  to  connect  parallel  mains  in  such  a 
fashion  that  water  can  be  fed  from  one  to  the  other  in  case  of 
emergency.  Valves  ought  to  be  put  on  the  hydrant  branches  for 
the  same  reason;  a  4-inch  branch  which  has  been  broken  during 
a  fire  will  waste  a  great  quantity  of  water.  The  method  of  con- 
ducting such  work  and  of  putting  in  service  pipes  to  buildings  is 
so  fully  explained  in  Mr.  Billings'  book  that  nothing  further 
needs  to  be  said.  The  principles  which  should  govern  the  de- 
sign of  the  system  of  street  mains  are  given  in  Chapter  XIX. 
There  should  be  plenty  of  blow-offs  at  low  places  so  that  the 
pipes  can  be  emptied  or  flushed  out  in  sections,,  and  if  any  hills 
have  to  be  surmounted  air  valves  should  be  placed  at  the  summits. 
Air  is  bound  to  collect  at  these  places,  and  there  are  a  number  of 


WATER-WORKS  MANUAL.  *09 

different  devices  on  the  market  for  allowing  it  to  escape  automati- 
cally; if  they  are  not  employed  trouble  generally  ensues.  It  is  also 
desirable  to  locate  gates  on  the  summits  whenever  practicable.  In 
case  of  an  accident  to  any  one  of  them  water  can  be  drawn  off 
through  the  blow-offs  at  the  bottom  of  each  of  the  inclines  leading 
to  the  summit,  and  the  valve  will  thus  be  freed  from  water  pres- 
sure for  easy  repairing.  If  it  was  located  at  a  low  point  this  would 
be  very  difficult  to  accomplish. 

It  is  frequently  necessary  to  divide  the  distribution  pipes  in  the 
streets  into  two  or  more  sections,  in  each  of  which  the  elevation 
varies  within  limits  of  30  to  50  pounds.  Each  of  these  sections 
is  commonly  called  a  service  district.  The  reason  for  this  prac- 
tice is  to  be  found  in  the  necessity  of  keeping  the  pressure  on 
plumbing  within  the  limits  of  its  strength;  with  street  pressures 
over  75  pounds  ordinary  plumbing  is  liable  to  leak  and  wear  out 
rapidly. 

In  some  cities  it  is  possible  to  supply  the  different  services 
from  independent  sources,  but  when  this  is  impracticable  it  is 
often  necessary  to  let  the  water  from  the  high-service  district 
pass  to  the  others  through  pressure  reducing  valves.  These  are 
so  arranged  that  the  pressure  on  the  lower  side  of  the  valve  can 
never  rise  about  the  amount  fixed  when  the  apparatus  is  adjusted. 
If  the  draft  in  the  lower  district  is  light  the  valve  allows  but  a 
small  amount  to  flow  through,  but  when  a  fire  breaks  out  and  the 
hose  streams  are  in  use  the  valve  opens  wide  automatically  and  al- 
lows a  large  volume  of  water  to  flow  so  long  as  the  draft  keeps  the 
pressure  down.. 

SUBMERGED  PIPE. 

Although  the  chapter  on  intakes  has  given  some  information 
on  methods  of  laying  submerged  pipe  the  subject  deserves  fur- 
ther consideration.  In  the  first  place  a  distinction  should  be 
drawn  between  pipes  having  flexible  joints  and  those  without. 
The  purpose  of  these  joints  is  to  enable  the  pipes  to  follow  the 
profile  of  the  trench  by  bending  without  fracture  or  leakage.  The 
first  joint  of  this  nature  of  which  the  writer  has  any  record  was 
designed  by  James  Watt  for  the  Glasgow  Water- Works  Com- 
pany and  used  in  1810  in  a  1,000-foot  line  of  15-inch  pipe  across 
the  Clyde.  The  bell  of  this  joint  was  a  hemisphere.  The  spigot 
fitted  closely  within  it  and  was  cast  with  the  pipe.  It  was  con- 
siderably more  than  a  hemisphere,  so  as  to  allow  bending,  and  was 


210 


WATER-WORKS  MAXUAL. 


WATER-WORKS  MANUAL.  211 

held  within  the  bell  by  a  lead  ring  pressed  firmly  into  place  by  a 
ring  of  angle  iron  bolted  to  the  bell.  The  joint  generally  used 
in  this  country  was  designed  by  John  F.  Ward,  M.  Am.  Soc.  C.  E. 
Most  pipe  manufacturers  illustrate  it  or  some  modification  in  their 
catalogues  and  it  is  shown  in  Trautwine's  Handbook,  so  it  is  un- 
necessary to  do  so  here.  All  flexible  joints  are  liable  to  leak 
somewhat  under  light  pressures,  unless  they  are  laid  in  their  final 
position  under  a  strong  tensile  strain — which  will  calk  them  thor- 
oughly. If  the  work  is  to  be  done  in  a  strong  current  over  a  rocky 
bed,  it  will  be  of  advantage  to  use  plenty  of  these  flexible  joints, 
9-foot  instead  of  12-foot  lengths  of  pipe,  and  reinforce  the  bell  of 
each  joint  with  a  wrought  iron  band,  about  3  inches  wide  and  1 
inch  thick,  shrunk  firmly  in  place  around  the  outside  rim.  It  is 
also  desirable  to  round  off  the  inner  edge  of  the  bell  slightly  so 
that  the  lead  forming  the  joint  will  not  be  cut  when  the  joint 
is  bent. 

The  usual  manner  of  laying  pipes  with^such  joints  was  intro- 
duced many  years  ago  by  Mr.  Ward.  Figure  41  shows  the  method 
as  adopted  at  Camden,  N.  J.  A  scow  is  provided  which  has  a 
launching  way  of  timbers  hung  over  the  side  near  its  bow,  the 
free  end  trailing  on  the  bottom.  A  few  pipes  are  calked  together 
on  this  launching  way  and  the  scow  is  then  pulled  ahead  far 
enough  to  allow  a  new  lot  to  be  calked  in  the  end  of  the  first.  It 
is  generally  unnecessary  to  make  each  joint  of  the  flexible  type. 
Sometimes  no  launching  way  whatever  is  used,  the  end  of  the 
pipe  last  jointed  being  held  by  tackle  while  another  section  is 
jointed  to  its  end.  This  is  similarly  supported  while  the  scow  is 
pulled  ahead  a  pipe  length  ready  for  a  repetition  of  the  operation. 

A  rather  unusual  method  of  laying  such  a  main  is  described  in 
Volume  xxxiii.  of  the  "Transactions"  of  the  American  Society 
of  Civil  Engineers,  by  Mr.  L.  L.  Tribus,  who  adopted  it  in  laying 
a  line  of  12-inch  pipe  on  the  ice  in  Morris  Lake,  Xew  Jersey. 
The  ice  was  10  to  14  inches  thick.  A  Ward  joint  was  used  every 
48  feet,  there  being  two  lengths  of  pipe  with  ordinary  bell  joints, 
then  a  pipe  with  a  Ward  spigot,  then  one  with  a  Ward  hub,  each 
length  being  12  feet  long.  These  were  laid  on  the  ice,  blocks 
being  put  underneath.  It  was  then  lowered  by  tackle  in  water 
from  6  to  12  feet  deep,  about  50  feet  at  a  time.  After  it  was  laid, 
it  could  be  seen  gradually  settling  in  the  mud,  owing  to  the  clear- 
ness of  the  water. 


312  WATER- WORKS  MANUAL. 

Sometimes  submerged  pipe  lines  are  pulled  across  a  waterway 
from  one  shore  to  the  other;  an  instance  of  this  method  is  de- 
scribed by  Thomas  H.  McCann  in  the  volume  of  "Transactions" 
just  mentioned.  In  this  case  it  was  necessary  to  lay  a  20-inch 
force  main  across  two  tidal  rivers,  each  about  400  feet  wide  with  a 
firm  mud  bottom  and  slopes  of  about  12  in  100,  the  range  of  tide 
being  about  5  feet.  Xo  dredging  was  done.  Ward  joints  were 
used,  the  calking  being  done  on  one  shore  and  the  pipe  then 
hauled  across  the  river  as  each  joint  was  completed,  a  40-horse- 
power  engine  and  heavy  chains  being  used  for  the  purpose.  As 
each  joint  entered  the  water,  two  ordinary  oil  barrels  were 
lashed  firmly  to  the  pipe  to  buoy  it.  When  the  end  of  the  main 
had  reached  far  enough  up  the  opposite  shore  to  allow  for  the  ex- 
tension due  to  settlement,  the  barrels  were  gradually  cut  loose  and 
the  pipe  settled  slowly  to  the  bottom.  After  the  water  was  turned 
on,  a  diver  was  sent  down  to  examine  the  joints  but  he  found  no 
leaks,  and  none  have  since  been  detected,  although  an  examination 
has  been  made  every  summer  by  a  diver.  The  main  is  under  a 
pressure  of  about  90  pounds.  The  maximum  depth  of  water  in 
both  rivers  is  21  feet. 

A  number  of  submerged  pipes  have  been  laid  by  Thacher  & 
Shirley,  of  Toledo,  in  which  a  draw  joint  is  employed.  In  their 
work  part  of  the  pipe  is  of  the  usual  type  and  part  has  a  spigot  end 
which  is  turned  to  a  cone.  This  cone  is  inserted  in  a  bell  and  a 
lead  joint  carefully  poured  and  calked  about  it.  The  spigot  is 
then  withdrawn,  leaving  the  lead  in  the  bell.  The  pipes  are  joint- 
ed on  shore  into  sections  several  pipes  long,  with  a  turned  spigot 
at  one  end  and  a  lead  filled  bell  in  the  other.  The  ends  are  closed 
by  bulkheads,  and  the  sections  floated  with  the  aid  of  barrels  to 
the  place  where  they  are  to  be  laid.  There  they  are  sunk  by  tak- 
ing oft'  the  bulkheads  and  casks  and  lowering  them  by  derricks  on 
scows.  When  a  section  is  close  to  the  bottom,  its  spigot  end  is 
carefully  guided  by  a  diver  into  the  bell  of  the  section  already 
in  place.  When  it  is  in  position,  it  is  drawn  into  the  bell  by 
means  of  bolts  connecting  the  two  ends,  and  the  diver  completes 
the  work  by  calking  the  joint.  Pipes  6  feet  in  diameter  have  been 
laid  in  this  way. 

In  one  instance  where  a  16-inch  submerged  pipe  had  to  be  laid 
in  about  20  feet  of  water,  the  engineer  in  charge,  Mr.  E.  C.  Cooke, 
employed  a  light  pile  trestle  on  which  the  pipe  was  calked  in  a 


WATER-WORKS  MANUAL.  213 

piofile  corresponding  to  the  undulating  surface  on  which  it  was  to 
rest.  The  joints  were  further  strengthened  by  wooden  frames 
clamped  tightly  about  them,  so  as  to  secure  them  from  bending 
and  tension.  When  the  main  was  calked  and  tied  in  this  man- 
ner, it  was  lowered  by  slings  at  each  trestle  bent. 

Pipe  laying  from  a  trestle  by  some  modification  of  this  plan  is 
probably  the  usual  method  for  submerged  work  across  small 
streams.  Owing  to  the  slight  flexibility  of  well-calked  joints  of 
the  regular  bell  and  spigot  type,  any  slight  variation  in  the  rate  of 
lowering  at  different  points  of  the  main  is  not  a  serious  matter, 
although,  of  course,  great  care  should  be  taken  to  make  the  motion 
uniform  at  every  point.  If  the  bed  of  the  stream  is  sandy,  the 
current  will  sometimes  cut  out  the  sand  below  the  pipe  when  it 
draws  near  the  bottom,  and  if  this  is  not  done  a  jet  of  water  direct- 
ed on  the  bottom  will  sometimes  enable  a  trench  to  be  quickly  ex- 
cavated, as  in  the  case  of  the  Escanaba  intake  pipe  described  in  the 
chapter  on  intakes.  Where  the  excavation  is  in  soft  material  and 
the  water  is  shallow,  scoops  on  the  end  of  long  poles  have  proved 
the  most  successful  tools  for  digging  the  trench  in  several  cases. 

The  use  of  rafts  of  oil  barrels  is  not  unusual  where  submerged 
pipe  has  to  be  laid.  After  the  trench  was  dug  in  one  such  case, 
two  lines  of  barrels  were  held  by  frames  so  as  to  form  a  raft  from 
shore  to  shore.  Along  the  center  of  this  raft  was  an  open  space 
spanned  by  transverse  wedge  timbers  on  which  the  pipes  were  calk- 
ed together  in  the  usual  manner;  the  main  was  16  inches  in  di- 
ameter, 300  feet  long  and  terminated  at  each  end  in  a  bend  rising 
at  an  angle  of  about  45  degrees.  When  it  was  entirely  completed 
timbers  supported  by  blocks  were  placed  across  the  pipe  at  fre- 
quent intervals,  and  the  pipe  hung  by  ropes  from  these  timbers. 
It  was  first  raised  a  little  to  allow  the  wedges  to  be  removed,  and 
was  then  sunk  slowly  into  place  by  slacking  off  the  rope  slings. 

A  leak  in  a  submerged  water  main  at  Port  Huron  was  repaired 
in  a  novel  manner  by  Mr.  Hugh  F.  Doran.  The  pipe,  which  was 
16  inches  in  diameter,  had  been  split  for  about  3  feet  by  a  dredge. 
A  half  cylinder  of  wood,  conforming  to  the  outside  diameter  of 
the  pipe,  was  made  of  I^x2-inch  strips  or  staves,  fastened  together 
at  each  end  by  a  flexible  band.  On  the  inside  of  this  wooden 
cylinder  was  tacked  a  sheet  of  £-inch  rubber  packing,  and  a  sheet 
of  light  steel  boiler  plate  was  placed  on  the  outside  in  a  similar 
manner.  This  patch  was  then  placed  over  the  break  by  the  diver 


214  WATER-WORKS  MANUAL. 

and  securely  fastened  to  the  pipe  with  4xl-inch  wrought-iron 
bands,  made  to  the  circle  of  the  patch  and  drawn  together  by 
1-inch  bolts,  the  space  between  the  bands  being  7  inches.  By 
this  means  the  pipe  was  made  perfectly  tight  and  has  repeatedly 
withstood  fire-pressure. 

It  sometimes  happens  that  a  pipe  must  be  carried  over  a 
stream  or  gorge,  rather  than  under  it,  and  it  is  thus  directly  ex- 
posed to  the  weather.  If  the  pipe  is  less  than  500  feet  in  length, 
practical  experience  in  New  England  shows  that  the  lead  joints 
will  take  up  all  the  variations  in  length  due  to  temperature 
changes.  Usually  the  pipe  can  be  hung  from  a  bridge,  but  if  it 
cannot  and  the  span  is  short,  it  may  be  trussed  by  tie  rods  and 
struts  below  it  so  as  to  form  the  upper  chord  of  a  queen  post  truss 
of  sufficient  strength  to  support  its  own  weight  and  that  of  the 
water  it  contains.  This  has  been  done  at  several  places,  but  the 
only  case  of  which  the  writer  has  definite  records  was  at  Lynch- 
burg,  Va  . 

If  it  is  certain  there  will  always  be  a  flow  of  water  in  the  pipe 
there  is  no  reason  for  protecting  it  by  a  non-conducting  covering, 
although  this  is  usually  done.  The  usual  plan  is  to  cover  the  pipe 
with  hair  felt,  then  leave  an  air  space  all  about  it  and  finally  put 
a  sort  of  double  housing  over  it  with  the  space  between  the  outer 
and  inner  planking  filled  with  sawdust.  The  housing  must  be 
water-tight  to  be  of  much  use. 

CLAY    PIPES    AND    OPEN    CHANNELS. 

It  is  sometimes  possible  to  conduct  wrater  for  a  considerable  dis- 
tance along  the  hydraulic  grade  line — and  to  substitute  a  vitrified 
clay  pipe  line,  timber  flume  or  open  channel  for  the  more  ex- 
pensive iron  pipe.  The  velocity  of  flow  in  a  vitrified  clay  pipe  line 
may  be  estimated  by  means  of  the  following  formula,  deduced  by 
Mr.  Eudolph  Hering  from  the  Kutter  formula. 
v  =  Ar  |/s  -f-  (B  +  yr). 

In  this  formula  s  is  the  slope  or  grade,  v  is  the  velocity  in  feet 
per  second,  and  r  is  the  hydraulic  radius,  the  quotient  of  the  cross- 
section  of  the  stream  of  water  in  square  feet  divided  by  the  wetted 
perimeter  of  the  channel  in  feet.  For  vitrified  pipe  A  may  be 
taken  as  188  and  B  as  0.64.  For  a  carefully  made  flume  of  planed 
timber  A  may  be  taken  as  200  and  B  as  0.55.  The  discharge  in 
cubic  feet  per  second  is  found  by  multiplying  the  velocity  by  the 
cross-section  of  the  stream.  The  flow  through  an  open  paved 


WATSR-K  ORKS  MANUAL.  215 

channel  of  small  size  depends  on  so  many  conditions  difficult  to 
specify  exactly  that  it  would  be  idle  to  discuss  the  subject  here. 

Vitrified  clay  pipe  for  water  conduits  were  first  brought  prom- 
inently before  engineers  in  1888  by  Mr.  S.  E.  Babcock  in  a  paper 
before  the  American  Water-works  Association  describing  such 
pipe  lines  in  the  water-works  systems  of  Amsterdam,  Little  Falls 
and  Johnstown,  N.  Y.  In  no  place  are  they  more  than  a  couple 
of  feet  below  the  hydraulic  grade,  and  they  form  part  of  a  system 
in  which  open  channels  and  cast-iron  pipe  are  also  employed.  In 
the  plant  at  Little  Falls  the  pipe  was  required  to  have  a  thickness 
of  one-twelfth  of  the  diameter  and  be  fitted  with  hubs  3  inches 
deep  and  large  enough  in  diameter  to  allow  for  a  f-inch  cement 
joint  all  around  the  circumference  of  the  spigot.  Five  per  cent, 
variation  in  the  dimensions  was  allowed  during  inspection.  The 
pipes  were  well  glazed  all  over  and  any  which  had  a  fire  crack  con- 
sidered injurious  by  the  engineer  were  rejected.  Pimples  and 
blisters  on  the  interior  surface  liable  to  check  the  flow  of  water, 
were  other  grounds  of  rejection.  Pipe  with  slight  cracks  or  breaks 
in  the  socket  were  accepted,  for  such  defects  cause  no  trouble  in  a 
conduit  not  subject  to  internal  pressure  of  any  appreciable  amount. 

The  method  of  laying  is  best  indicated  by  quoting  from  the 
specifications: 

"The  joints  of  the  vitrified  pipes  shall  be  made  of  Portland 
cement  mortar  in  combination  with  gaskets  of  clean,  sound  hemp 
yarn  or  jute,  braided  or  twisted,  and  tightly  driven,  as  follows: 

"Each  length  or  strand  of  the  jute  shall  be  of  a  diameter  to 
loosely  fill  the  width  of  joint,  and  shall  be  thoroughly  soaked  in  a 
Portland  cement  mortar,  made  of  thick  paste  of  clean  cement  and 
water,  and  shall  be  of  a  length  to  go  once  around  the  circumference 
of  the  pipe  and  lap  over  two  or  three  inches.  This  shall  be  driven 
home  with  calking  tools,  and  shall  be  succeeded  by  a  sufficient 
number  of  strands  to  fill  the  joint  room  to  within  one-half  an 
inch  of  the  outside  of  bell,  breaking  joints  with  the  laps.  All 
driven  home  and  thoroughly  joined  together.  The  joint  shall 
then  be  finished  by  filling  the  remaining  one-half  inch  of  joint 
room  with  a  clear  Portland  cement  mortar,  the  joint  room  when 
finished  being  completely  filled  all  around  the  pipe  to  the  outside 
lines  of  the  bells. 

"The  contractor  will  furnish  the  pipe  layer  with  a  bag,  stuffed 
with  shavings  or  hay,  of  a  size  sufficient  to  fit  the  pipe  ratBer 


216  WATER-WORKS  MANUAL. 

tightly,  with  a  rope  about  ten  yards  in  length  fastened  at  one  end 
to  the  mouth  of  the  bag.  The  bag  must  be  placed  in  the  first  pipe, 
the  rope  passing  through  each  pipe  as  it  is  laid  down.  After  the 
joints  are  made,  the  bag  is  then  to  be  drawn  forward  at  such  times 
before  the  cement  has  set  as  to  smooth  off  and  produce  a  true  sur- 
face at  each  cement  joint  and  a  continuous  thin  coating  of  cement 
on  the  lower  half  of  the  pipe." 

These  specifications  call  for  a  good  class  of  sewer  pipe  laying, 
and  there  should  be  no  difficulty  in  having  them  carried  out,  or 
others  of  an  equivalent  nature.  The  cost  of  the  Little  Falls  con- 
duit, consisting  of  10,000  feet  of  20-inch  vitrified  pipe  on  a  grade 
of  8  feet  per  mile,  18,500  feet  of  18-inch  on  a  grade  of  13  feet 
per  mile,  900  feet  of  15-inch  on  a  grade  of  79  feet  and  1,000  feet 
of  12-inch  on  a  105-foot  grade,  was  $45, 544,  or  approximately  $1.50 
a  foot,  while  the  portions  of  the  same  conduit  which  were  laid 
with  cast-iron  pipe  cost  nearly  $2.60  per  foot.  In  the  ten  years 
the  pipe  has  been  in  service  it  has  been  free  from  breaks. 

Such  a  conduit  must  have  no  valve  or  gate  except  at  its  upper 
end,  for  if  the  flow  of  water  in  it  should  be  checked  it  will  be  sub- 
jected to  a  hydrostatic  head  which  may  cause  serious  trouble.  If 
there  is  no  gate  anywhere  along  its  line,  such  danger  is  reduced  to 
a  minimum.  The  pipe  must  discharge  into  a  well  or  reservoir  of 
some  kind,  for  the  same  reason. 

Open  channels  for  conveying  water  for  domestic  purposes  have 
the  serious  fault  of  allowing  grass,  leaves  and  other  impurities  to 
enter  the  supply,  and  generally  permit  a  considerable  proportion 
of  the  water  to  become  lost  by  percolation  into  the  earth.  On  the 
other  hand,  their  small  cost  makes  their  use  advisable  where  the 
water  is  ample  in  quantity  and  not  exposed  to  contamination  dur- 
ing its  flow  through  the  channel.  It  has  been  found  in  some  por- 
tions of  the  West  that  an  open  channel  lined  with  cement  to  pre- 
vent percolation  is  the  cheapest  satisfactory  method  of  distributing 
water  over  sandy  plains  for  irrigating  purposes;  and  in  a  number 
of  water-works,  open  paved  channels  or  beds  of  natural  brooks  are 
employed.  Flumes  of  plank  calked  with  oakum  are  used  exten- 
sively in  the  West,  but  the  cost  of  constructing  them  for  small 
quantities  of  water  will  probably  be  equal  or  greater  than  the  ex- 
pense of  vitrified  clay  or  spiral  riveted  pipe  of  the  same  capacity. 

If  an  open  channel  can  be  introduced  to  advantage,  care  should 
be  taken  to  avoid  such  dimensions  that  the  velocity  will  wear  away 


WATER-WORKS  MANUAL.  217 

the  sides  or  bottom,  if  they  are  of  earth.  Where  the  slope  is  too 
great  for  an  open  channel  to  be  constructed  in  one  unbroken  line, 
it  may  be  fitted  with  a  series  of  falls  between  which  a  satisfactory 
grade  can  be  secured.  Just  before  each  fall  is  reached  the  chan- 
nel should  be  narrowed  somewhat  to  allow  for  the  greater  ve- 
locity acquired  by  the  water  before  it  drops.  An  apron 
of  some  sort,  or  a  water  cushion,  should  be  provided  to  resist  the 
erosion  of  the  water  where  it  strikes,  provided  the  quantity  is  large 
or  the  fall  is  great.  Open  channels  are  used  in  connection  with 
vitrified  pipe  lines  on  both  the  Amsterdam  and  Little  Falls  con- 
duits, and  in  the  case  of  the  latter  one  of  these  channels,  which  is 
quite  steep,  has  a  series  of  low  dams  or  riffles  at  frequent  intervals, 
which  were  introduced  to  secure  a  thorough  aeration  of  the  water. 

Where  an  open  channel  carries  water  in  which  considerable 
sand  may  be  held  in  suspension,  it  is  well  to  pass  it  through  a  sand 
catcher.  This  is  merely  a  chamber  or  basin  large  enough  to  check 
the  velocity  of  the  water  considerably.  The  result  of  such  a  dim- 
inution of  velocity  is  the  settlement  of  the  sand  and  coarse  silt  to 
the  bottom  of  the  chamber,  which  should  have  a  fairly  large  blow- 
off  pipe  fitted  with  some  sort  of  a  sluice  gate.  When  enough  sand 
has  been  intercepted  to  warrant  clearing  the  basin,  the  gate  is 
opened  and  the  sand  flushed  away  through  the  pipe  to  some  place 
where  it  will  do  no  harm.  An  ordinary  gate  valve  is  not  adapted 
for  such  use  because  it  is  liable  to  have  the  valve  cut  by  the  sand 
when  it  rushes  out  of  the  chamber.  The  blow-off  pipe  should  be 
of  fairly  large  diameter  so  as  to  empty  the  chamber  quickly,  but 
not  so  large  that  the  velocity  of  the  water  will  be  inadequate  to 
clean  out  the  sand. 

In  case  it  is  desired  to  calculate  the  flow  through  an  open  chan- 
nel, much  assistance  can  be  secured  from  No.  84  of  Van  Nostrand's 
Science  Series,  "The  Flow  of  Water  in  Open  Channels,  Pipes,  Etc/' 
by  the  late  P.  J.  Flynn. 


CHAPTER  XVIII.— SEEVICE  RESERVOIRS  AND  STAND- 
PIPES. 

The  bona-fide  direct-pressure  system  of  water-works  has  now 
passed  into  history,  for  no  one  acquainted  with  even  the  elements 
of  water-works  management  thinks  of  building  a  plant  without  a 
small  reservoir,  stand-pipe  or  elevated  tank  to  supply  the  sudden 
large  demands  for  water  for  fires,  while  the  pumping  machinery  is 
being  speeded  up  to  the  increased  duty.  It  is  now  settled  practice 
that  every  works  depending  upon  pumping  should  have  some  sort 
of  a  service  reservoir  or  stand-pipe.  It  furnishes  a  supply  of  water 
during  the  night,  so  that  the  pumps  may  be  shut  down  and  the  fires 
banked,  thereby  saving  coal  and  attendance,  and  it  equalizes  the 
head  against  which  the  pumps  work  and  makes  their  operation 
more  economical  in  consequence.  Even  with  gravity  supplies  ser- 
vice reservoirs  are  often  advisable,  as  their  construction  may  cost 
less  than  the  difference  in  expense  between  a  long  conduit  large 
enough  to  supply  the  maximum  demanq}  for  fire  and  domestic  pur- 
poses and  a  smaller  conduit  ample,  with  a  storage  reservoir,  to 
furnish  the  same  service. 

Reservoirs  can,  of  course,  only  be  employed  where  the  topo- 
graphy is  such  that  an  elevated  site  is  available  for  their  construc- 
tion; if  the  country  is  flat  a  stand-pipe  or  water  tower  must  be  used. 
If  a  site  can  be  found,  the  first  question  to  be  settled  is  the  storage 
capacity  to  be  given  the  basin;  if  the  cost  of  construction  will  be 
comparatively  small,  storage  for  several  days  should  be  provided. 
In  this  connection  attention  should  be  paid  to  the  fact  that  such  a 
reservoir  has  a  decided  influence  on  the  size  of  the  pumping  plant 
and  force  main.  These  need  only  be  designed  to  furnish  the  re- 
quired volume  of  water  when  working  steadily  during  the  day- 
time. Uniform  operation  under  these  conditions  means  that  the 
size  of  the  plant  and  main  can  be  kept  down,  the  cost  of  operation 
reduced,  and  but  one  force  of  attendants  need  be  employed.  The 
pipe  leading  from  the  reservoir  must  be  sufficiently  large  to  supply 


WATER-WORKS  MANUAL. 


219 


the  maximum  domestic  and  fire  draft,  and  may  therefore  be  of 
larger  diameter  than  the  force  main. 

If  the  water  comes  from  wells  it  should  be  protected  from  the 
sunlight,  which  makes  some  sort  of  covering  necessary  at  the  stand- 
pipe  reservoir.  The  heavy  masonry  roofs  of  foreign  plants  are  too 
costly  for  this  country,  and  the  writer  believes  that  the  least  expen- 
sive device  for  small  work  will  probably  be  arched  vaults  of  brick- 
work or  the  use  of  light  steel  I  beams  with  terra-cotta  filling  such 
as  is  used  for  floors  in  high  buildings.  The  latter  plan  has  never 


FIGURE  4_'.— ELLIPTIC  GROINED  ARCHES,  ASHLAND. 

been  tried,  to  his  knowledge,  but  some  rough  estimates  indicate 
that  it  is  worthy  of  consideration.  These  roofs  can  be  covered 
with  earth  and  will  keep  the  water  from  freezing  except  in  very 
severe  weather.  If  the  roof  is  to  be  above  ground,  wood  or  iron 
framing  and  shingling  are  doubtless  as  good  as  more  expensive 
concrete  arches,  for  ice  will  probably  form  during  cold  weather 
no  matter  what  type  of  construction  is  followed. 

The  groined  brick  arches  used  at  Ashland,  Wis.,  by  Mr.  William 
Wheeler,  and  shown  in  Figure  42  are  among  the  most  interesting 
masonry  roofs  built  in  this  country.  The  brick  piers  are  15f  feet 
apart  in  the  clear  and  the  elliptical  arches  have  3J  feet  rise.  In  a 
description  of  this  work  in  the  "Journal"  of  the  New  England 


220 


WATERWORKS  MANUAL. 


FIGURE  43.— SUPPORTS  FOR  ARCHES,  NEWTON  RESERVOIR. 


WATER-WORKS  MANUAL.  221 

Water-Works  Association,  Mr.  Wheeler  states  that  the  arch  rings 
are  about  5  inches  thick  and. consist  of  two  courses  of  bricks  laid 
flatwise  in  Portland  cement  mortar.  The  spandrels  of  the  arches 
and  the  spaces  over  the  piers  and  adjacent  walls  are  filled  and  cov- 
ered with  a  backing  of  Portland  cement  concrete  up  to  a  general 
level  of  4  feet  above  the  spring  of  the  arches,,  but  sloping  down  to  a 
height  of  only  2  feet  above  the  springing  line  at  the  rear  of  the  out- 
side walls.  The  bricks  in  the  arches  are  laid  in  uniform  horizontal 
courses,  and  cut  or  mitred  to  fit  the  angles  of  their  intersections, 
except  in  a  few  courses  next  the  springing  lines  and  also  at  and 
near  the  crowns,  where  the  corresponding  courses  of  the  intersect- 
ing arches  are  neatly  bonded  with  or  into  each  other  without  cut- 
ting. There  are  openings  at  the  alternate  intersections  of  the 
arches  to  afford  access  to  the  space  below.  Upon  the  concrete 
backing  which  overlies  the  covering  arches  2  feet  of  earth  has  been 
placed  and  seeded. 

The  construction  of  such  vaulting  may  give  so  much  trouble  to 
inexperienced  contractors  that  a  simpler  system  may  prove  desir- 
able in  some  cases.  In  Figure  43  is  shown  the  system  of  brick  piers 
and  lintels  built  at  Newton,  Mass.,  by  the  late  Albert  F.  Noyes  to 
support  a  roof  of  parallel  brick  barrel  arches.  It  is  probable  that 
most  masons  would  prefer  to  build  such  a  roof  and  might  put  in  a 
lower  tender  for  it,  although  it  requires  more  masonry  than  the 
groined  arch  which  is  really  little  if  any  more  difficult  to  construct 
if  a  competent  engineer  is  on  hand  to  start  the  work  properly. 

Service  reservoirs  must  be  lined  on  the  bottom  and  slopes  to 
make  them  water-tight.  Formerly  nothing  but  puddle,  protected 
on  the  slopes  by  dry  stone  paving,  was  used  for  this  purpose.  Pud- 
dle of  good  material  properly  laid  under  the  direction  of  an  ex- 
perienced engineer  will  make  a  tight  basin.  Unfortunately,  how- 
ever, if  the  slopes  are  steep  or  the  puddle  contains  much  clay,  the 
slope  lining  may  slide  to  the  bottom  when  the  basin  is  emptied 
after  a  long  period  of  service.  Moreover,  really  good  puddle  ma- 
terial is  hard  to  find  in  many  localities,  and,  even  when  found,  it 
is  not  always  well  made. 

It  was  but  natural,  therefore,  for  engineers  to  line  many  of  these 
basins  with  concrete.  Frequently  puddle  is  first  laid  and  then  the 
concrete  placed  over  it.  Well  made  concrete  is  an  excellent  ma- 
terial for  this  purpose;  but  unfortunately  it  is  not  alwayswell  made. 
Even  when  of  good  quality  it  must  be  placed  in  such  a  manner 


222  WA  TER  WORKS  MA  N UAL. 

that  the  puddle  or  earth  on  which  it  rests  cannot  be  washed  from 
below  it  by  percolation  down  the  slopes  under  the  lining  or 
by  the  pressure  of  the  stored  water.  Of  late  years  engineers  have 
sought  additional  security  by  covering  the  concrete  with  asphalt, 
and,  in  some  cases,  have  abandoned  the  concrete  entirely  and  used 
brick  and  asphalt  in  its  place. 

COXCRETE-LIXED  RESERVOIRS. 

Concrete  of  a  high  grade  is  not  often  laid  in  large  continuous 
sheets.,  and  some  engineers  hold  that  it  cannot  be  done  without 
cracks  forming.  As  a  matter  of  fact,,  continuous  concrete  reservoir 
linings  have  been  constructed  without  such  cracks  appearing,  and, 
owing  to  the  slight  range  of  temperature  of  such  a  lining  and  con- 
sequent freedom  from  expansion  and  contraction,  the  writer  be- 
lieves they  should  be  built  if  it  seems  probable  good  results  can  be 


FIGURE  44.— HAVERHILL  RESERVOIR  EMBANKMENT. 

obtained.  If  the  work  is  done  by  contract,  the  cement  should  be 
furnished  by  the  city,  not  only  to  insure  the  use  of  good  material 
but  also  to  keep  the  contractor  from  skimping  the  quantity.  One 
of  the  most  notable  instances  of  the  successful  construction  of  a 
continuous  lining  of  this  sort  is  afforded  by  the  Palatine  reservoir 
of  the  Havana  water-works,  of  which  Mr.  E.  Sherman  Gould  was 
the  engineer.  Here  one  foot  of  concrete  was  laid  in  two  6-inch 
courses  over  an  area  of  about  2.8  acres.  The  best  quality  of  Port- 
land cement  was  used,  and  the  concrete  was  mixed  in  the  propor- 
tion of  one  part  of  cement,  three  parts  of  sharp  calcareous  sand  and 
five  of  broken  limestone.  The  work  was  kept  scrupulously  clean, 
and  the  finished  concrete  was  sprinkled  with  water  by  hose  lines 
and  sprinkling  cans  for  one  to  two  weeks  after  it  was  laid.  The 
result  was  completely  successful. 

Such  expensive   construction  is  not  usually   followed  in  the 
United  States,  even  in  large  works.     At  the  service  reservoir  of 


WATER-WORKS  MANUAL. 


223 


the  Syracuse  water-works,  for  example,  the  concrete  lining  was  but 
9  inches  thick  and  made  of  one  part  of  hydraulic  cement,  two  parts 
of  sand  and  three  of  stone. 

The  high-service  reservoir  built  from  the  plans  of  Mr.  Free- 
man C.  Coffin  in  1898  to  store  9,000,000  gallons  of  water  for  sup- 
plying a  part  of  Haverhill,  Mass.,  may  be  taken  as  an  illustration 
of  good  practice  in  the  construction  of  such  basins.  The  basin  has 
a  maximum  depth  of  water  of  about  19  feet  and  is  partly  in  excava- 
tion. It  is  generally  advisable  to  utilize  the  excavated  material  if 
of  suitable  nature  in  the  banks,  as  was  done  in  this  case,  as  such 


FIGURE  44A.— HAVERHILL  GATE-HOUSE. 

a  course  tends  to  reduce  the  cost  of  the  work.  A  cross-section  of 
the  embankment  is  shown  in  Figure  44,  and  the  plan  of  the  gate 
house  in  Figure  44a.  A  brief  explanation  should  be  added  con- 
cerning the  gate-house  piping.  The  20-inch  supply  pipe  is  carried 
on  brick  piers  across  the  reservoir  to  the  opposite  side  from  the 
gate-house.  The  24-inch  inlet  pipe  is  taken  from  the  foot  of  the 
slope  just  in  front  of  the  gate-house.  The  20-inch  pipe  acts  as  a 
supply  to  the  pipe  system  when  the  pumps  are  not  working.  It 
has  a  gate  and  check  valve  which  prevents  the  water  from  run- 
ning back  into  the  main  without  first  passing  through  the  24-inch 
pipe  and  gate-chamber.  When  the  pumps  are  not  working  the 


224  WATER-WORKS  MANUAL. 

water  runs  through  the  24-inch  pipe  into  the  gate-chamber,  where 
it  passes  through  screens  and  then  through  a  check  valve,  placed 
on  an  offset,  into  the  20-inch  pipe.  There  is  a  vertical  10-inch 
pipe  in  the  gate-house  for  a  telemeter.  There  is  also  a  10-inch 
waste  pipe  with  a  branch  to  drain  the  gate-house,  which  passes 
beneath  the  latter  in  a  bed  of  concrete.  The  20-inch  main  is  em- 
bedded in  concrete  between  the  gate-house  and  the  outer  edge  of 
the  embankment.  The  concrete  around  each  of  these  pipes  is 
rectangular  in  cross-section,  6  inches  thick  above  and  below  them, 
and  10  inches  thick  on  the  sides,  with  two  cut-off  walls. 

The  following  extracts  from  the  specifications  make  further  ex- 
planations unnecessary: 

"Earth  Work. — All  the  ground  covered  by  the  reservoir  and  its 
embankments  shall  be  cleared  of  trees,  stumps,  stonfie,  roots,  turf 
and  other  vegetable  matter,  which  shall  be  separately  stored  in 
spoil  banks  at  such  points  as  the  engineer  may  direct.  The  soil 
is  to  be  removed  from  the  ground  to  be  covered  by  embankments, 
and  stored  in  spoil  banks  at  convenient  points  where  directed  for 
subsequent  use  on  the  surface  of  embankments.  Any  further 
amount  of  spoil  that  may  be  required  shall  also  be  stored  in  spoil 
banks  for  future  use. 

"All  embankments  or  fills  shall  start  from  a  well  prepared  base, 
fitted  for  incorporation  with  the  filling,  and  shall  be  formed  of 
earth  free  from  roots,  muck,  stones  measuring  more  than  2  inches  in 
any  diameter,  perishable  earth  or  other  unfit  material.  The  small 
stones  allowed  to  go  into  the  embankment  shall  not  form  more 
than  one  per  cent,  of  the  material,  and  shall  be  so  disposed  as  not 
to  be  liable  to  come  in  contact  with  each  other.  The  surface  soil 
suitable,  in  the  opinion  of  the  engineer,  for  the  purpose  is  to  be 
thoroughly  mixed  as  he  may  direct  with  other  material  and  used 
in  forming  the  banks. 

"If  in  the  opinion  of  the  engineer  other  earths  found  in  the  ex- 
cavation require  to  be  mixed  to  form  a  suitable  embankment,  they 
shall  be  mixed  in  such  manner  and  so  disposed  as  he  may  require. 
The  embankment  shall  be  carried  up  in  layers,  slightly  concave  in 
cross-section  but  level  longitudinally,  not  exceeding  4  inches  in 
thickness  before  rolling,  every  layer  to  be  carefully  rolled  with  a 
heavy  grooved  roller,  and  watered  more  or  less  when  and  as  re- 
quired. No  lumps  will  be  allowed  to  go  in,  and  all  possible  care 
taken  to  make  the  embankments  impervious  to  water.  The  earth  is 


WATER-WORKS  MANUAL.  225 

to  be  well  and  solidly  rammed  with  heavy  rammers  at  such  points 
as  cannot  be  reached  with  the  roller.  The  embankments  are  to  be 
overfilled  as  required,  in  no  case  more  than  12  inches  on  the  in- 
terior slopes,  which  shall  afterwards  be  dressed  off  and  will  be 
reckoned  as  excavation. 

"Soiling  the  Surfaces  and  Slopes. — The  soil  that  is  stored  in 
spoil  banks  as  above  stated  shall  be  placed  upon  the  top  and  slopes 
of  the  reservoir  in  a  layer  of  such  thickness  as  the  engineer  directs. 
It  shall  be  rammed  if  required  by  the  engineer  and  rolled  with  a 
heavy  hand  roller  and  trimmed  true  to  grade.  The  slopes  shall  be 
sodded  as  shown  on  the  drawings.  The  sods  to  be  approximately 
one  foot  square,  not  less  than  3  inches  thick,  and  have  a  good 
heavy  growth  of  grass  and  roots.  Each  sod  shall  be  pinned  to  the 
bank  with  a  wooden  pin  not  less  than  15  inches  long.  The  sod- 
ding shall  be  sprinkled  when  necessary  in  the  opinion  of  the  en- 
gineer. 

"Puddle. — The  puddle  shall  be  composed  of  good  pure  clay  and 
clean  gravel  in  such  proportions  as  shall  be  satisfactory  to  the  en- 
gineer. If  at  any  time  the  clay  provided  by  the  contractor  will,  in 
the  opinion  of  the  engineer,  bear  any  addition  or  admixture  of  any 
materials  from  the  excavation,  the  engineer  shall  determine  what 
proportion  of  such  material  shall  be  used,  and  from  what  part  of 
the  excavation  it  shall  be  taken,  and  in  what  manner  it  shall  be 
mixed  with  the  clay.  There  shall  be  no  material  from  the  exca- 
vation used  except  with  the  approval  of  the  engineer,  and  he  shall 
have  the  right  at  any  time  to  reject  any  clay  or  material  for  puddle 
that  is  not  satisfactory  to  him  or  that  will  not  in  his  opinion  be 
suitable  for  the  uses  for  which  it  is  intended,  and  such  material 
shall  be  immediately  taken  away  from  the  work. 

"The  bottom  of  the  reservoir  shall  be  prepared  for  the  reception 
of  the  concrete  or  puddle  in  a  manner  satisfactory  to  the  engineer. 
If  the  bottom  is  in  rock  or  ledge  it  shall  be  filled  up  to  the  grade 
of  the  under  side  of  the  puddle  or  concrete  and  well  tamped  or 
rolled  before  the  puddle  or  concrete  is  applied.  If  there  are  cracks 
or  fissures  in  the  ledge  they  shall  be  filled  with  concrete  or  mortar. 

"Reservoir  Lining. — The  reservoir  will  be  lined  over  the  bot- 
tom, on  the  inner  slope  and  in  the  embankment  as  shown  on  the 
drawings,  with  a  layer  of  hydraulic  cement  concrete  of  such  thick- 
ness as  the  engineer  directs,  not  less  than  4  inches.  This  concrete 
shall  be  put  on  in  one  layer,  carefully  leveled  up  and  lightly  ram- 


228  WATER-WORKS  MANUAL. 

med  until  the  mortar  flushes  to  the  surface;  then  suriaced  vttth 
Demerit  mortar  made  as  specified  herein.  The  surface  shall  be  im- 
mediately finished  off  with  trowels,  using  only  enough  mortar  to 
.smooth  up  and  make  a  fine,  close  surface.  In  finishing  this  sur- 
face, planks  shall  be  laid  upon  the  concrete  for  the  masons  to  walk 
and  work  upon.  As  soon  as  any  portion  is  finished  it  shall  be  at 
once  guarded  from  any  disturbance.  The  bottom  shall  be  the  last 
part  of  the  reservoir  to  be  finished,  and  shall  not  be  done  until 
special  orders  are  received  from  the  engineer.  The  concrete  shall 
be  protected  while  setting  from  the  sun  and  rain  by  canvas  or 
otherwise  in  a  manner  satisfactory  to  the  engineer.  [It  might  be 
well  in  most  cases  to  require  concrete  to  be  sprinkled  also,  when 
the  engineer  so  directs,  as  hot  dry  weather  may  injure  new  work 
even  when  covered  by  canvas  or  boards.] 

"Core  Wall. — There,  will  be  a  core  wall  of  rubble  masonry 
in  the  embankment  around  the  reservoir.  This  wall  will  be 
of  rubble  masonry  as  specified.  It  shall  be  laid  against  wooden 
forms  on  the  inside  face,  and  the  stones  shall  be  laid  with 
at  least  one-fourth  of  an  inch  between  the  forms  and  their  ex- 
treme points.  All  voids  between  the  stones  and  the  forms  shall 
be  filled.  No  stone  shall  be  laid  in  such  a  manner  as  to  project 
entirely  through  the  wall.  These  forms  shall  be  approximately  3 
feet  high  and  10  or  more  feet  long,  and  sufficiently  strong  to  re- 
tain their  shape.  There  shall  be  a  sufficient  number  of  them  to 
allow  the  cement  to  set  not  less  than  14  hours  before  their  removal. 
Any  voids  or  rough  places  in  the  face  of  this  wall  shall  be  pointed 
up  with  cement  mortar.  This  wall  shall  be  built  at  all  points  upon 
natural  undisturbed  earth  from  which  all  vegetable  matter  and 
loose  or  soft  material  have  been  removed.  It  shall  be  carried  up  at 
about  the  same  level  all  around  and  protected  from  the  sun  and 
rain  by  canvas  or  otherwise,  in  a  manner  satisfactory  to  the  en- 
gineer. 

"Plastering. — The  face  of  the  core  wall  shall  be  plastered  with 
a  thin  coat  of  neat  cement  mortar  which  shall  be  rubbed  in  and 
thoroughly  compacted  and  smoothed  with  trowels.  If  directed 
by  the  engineer  the  face  of  this  plaster  coat  shall  be  washed  with 
neat  cement  grout.  The  plastering  shall  be  protected  from  the 
sun  and  rain  in  a  manner  satisfactory  to  the  engineer. 

"Broken  Stone. — After  the  bank  is  carried  up  the  inner  slope 
will  be  dressed  true  to  line,  and  a  layer  of  broken  stone  or  screened 


WATER-WORKS  MANUAL.  227 

gravel,  averaging  about  6  inches  in  thickness,  will  be  applied. 
The  stone  used  for  this  purpose  must  be  sound,  and  shall  be  of 
such  size  that  they  will  all  pass  through  a  screen  of  3-inch  mesh 
and  none  of  them  will  pass  through  a  screen  of  1-inch  mesh.  The 
various  sizes  must  be  well  mixed  in  due  proportions,  and  when  laid 
in  place  shall  be  well  compacted  by  ramming.  All  broken  stone 
so  used  must  be  freed  from  fine  material  by  screening. 

"Slope  Paving. — The  inner  slope  is  to  be  paved  with  sound,  se- 
lected stone  of  good  shape  to  make  tight,  firm  work,  and  laid  dry. 
The  stones  are  not  to  be  less  than  10  inches  in  any  dimension,  and 
riot  less  than  one  cubic  foot  in  solid  contents.  The  paving  shall 
be  taken  from  ledge  or  boulders  large  enough  to  make  at  least  two 
pieces.  The  split  pieces  shall  form  the  face  of  the  slope  whenever 
possible.  Stones  with  flat  faces  may  be  laid  without  splitting, 
when  so  directed  by  the  engineer.  They  shall  be  laid  as  closely 
as  practicable.  Each  stone  shall  have  a  firm  bearing  in  the  broken 
stone  backing,  and  shall  be  thoroughly  pinned,  and  every  precau- 
tion shall  be  taken  to  make  each  stone  secure  in  its  place.  The 
lower  course  of  the  footing  of  the  slope  is  to  have  stone  of  the  full 
depth  of  the  surface  paving  and  the  broken  stone  backing,  and 
it  is  to  be  laid  in  such  manner  that  its  top  surface  shall  be  parallel 
to  the  slope  of  the  embankment.  This  lower  course  shall  be  laid 
in  cement  mortar. 

"Mortar. — The  sand  shall  be  clean,  sharp  and  free  from  loam. 
The  proportions  of  cement  to  sand  shall  be  those  designated  by  the 
engineer  for  different  parts  of  the  work.  They  shall  be  carefully 
mixed  in  the  following  manner:  About  one-half  of  the  sand  for  a 
batch  shall  be  spread  evenly  upon  a  tight  and  smooth  platform, 
with  low  sides  to  prevent  the  washing  away  of  the  cement.  The 
cement  shall  be  spread  evenly  upon  this  layer,  and  the  balance  of 
the  sand  spread  on  top.  The  whole  shall  be  turned  with  shovels 
and  thoroughly  mixed  dry.  Water  shall  be  applied  by  moderate 
sprinkling  from  a  sprinkler  nozzle.  Care  shall  be  taken  to  avoid 
an  excess  of  water  at  any  time,  and  the  total  amount  applied  shall 
only  be  sufficient  to  make  the  mortar  of  the  proper  consistency 
for  the  work  in  hand.  The  size  of  the  batch  to  be  wet  at  once 
shall  be  as  directed  by  the  engineer.  The  mortar  shall  be  freshly 
mixed  and  any  mortar  that  has  been  standing  long  enough  to  be- 
gin to  set  shall  not  be  used. 

"Concrete. — The  concrete  shall  be  formed  from  broken  stone 


2-2»  WATER-WORKS  MANUAL. 

or  sound  angular  stone  screened  from  gravel.  The  sand  screened 
from  the  stone  will  be  used  when  considered  suitable  by  the  engi- 
neer. In  screening  the  material,  three  screens  shall  be  used; 
namely,  one  with  2-inch  mesh  clearing  opening,  one  with  three- 
quarter-inch  mesh,  and  one  sand  screen,  the  size  of  mesh  to  be  sat- 
isfactory to  the  engineer.  All  material  not  passing  the  2-inch 
screen  will  be  rejected.  All  passing  the  2-inch  and  retained  on  the 
three-quarter-inch  screen  will  be  used  if  suitable  in  other  respects. 
All  material  passing  the  three-quarter-inch  screen  and  retained 
on  the  sand  screen  to  be  used  when  and  where  ordered  by  the  en- 
gineer. The  material  passing  the  sand  screen  to  be  used  for  sand 
if  considered  suitable  by  the  engineer. 

"Mixing  Concrete. — The  gravel,  which  must  be  clean  and  free 
from  dust  and  dirt,  shall  be  spread  upon  a  smooth,  tight  plat- 
form in  a  movable  frame.  This  frame  shall  be  of  gauged  dimen- 
sions for  holding  the  proper  amount  of  stone  for  a  batch  accord- 
ing to  the  direction  of  the  engineer.  The  gravel  shall  be  leveled 
off  with  the  top  of  the  frame  and  thoroughly  wetted.  The  cement 
and  sand,  mixed  dry  upon  an  adjacent  platform  as  specified  for 
mortar,  shall  be  uniformly  spread  upon  the  top  of  the  stone.  The 
frame  shall  be  lifted  off  and  the  material  carefully  and  thoroughly 
mixed  by  being  turned  over  with  shovels,  the  men  working  syste- 
matically under  the  direction  of  the  engineer.  If  additional 
water  is  required,  it  shall  be  moderately  sprinkled  on  the  material 
from  a  sprinkler  nozzle,  care  being  taken  not  to  wash  out  the  ce- 
ment or  to  put  on  at  any  time  an  excess  of  water  and  to  leave  the 
concrete  too  dry  rather  than  too  wet.  If  machine  mixing  is  adopt- 
ed, the  machinery  and  the  method  shall  be  satisfactory  to  the  en- 
gineer. 

"Placing  the  Concrete. — All  concrete  shall  be  placed  in 
horizontal  layers  about  6  inches  in  thickness  unless  otherwise  di- 
rected by  the  engineer.  It  must  be  deposited  in  such  a  manner 
that  there  will  be  no  separation  of  coarse  from  fine  material.  It 
shall  be  lightly  rammed  until  the  mortar  flushes  to  the  surface. 
It  shall  be  deposited  quickly  after  it  is  mixed,  and  as  far  as  pos- 
sible the  placing  of  concrete  shall  be  continuous.  In  joining  new 
work  to  that  which  is  set  or  practically  set,  such  precautions  of 
cleaning,  wetting  and  bonding  shall  be  observed  as  the  engineer 
directs. 

"Bubble  Masonry. — All  stone  masonry  is  to  be  laid  in  mor- 


WATER- WORKS  MANUAL.  2-9 

tar  such  as  above  described,  and  shall  be  well  bonded  with 
sound,  angular  stones,  laid  on  their  natural  beds,  and  so  as  to 
break  joints  sufficiently  for  strong  work.  All  parts  of  the  walls 
are  to  be  carried  up  at  a  uniform  rate,  so  that  the  entire  surface 
shall  be  at  about  the  same  level  as  the  work  progresses.  The 
stones  are  to  be  properly  moistened  before  laying  in  mortar.  Kub- 
ble  masonry  shall  be  so  laid  as  to  be  absolutely  without  voids. 
Each  stone  shall  be  completely  surrounded  with  mortar.  All 
joints  shall  be  as  small  as  the  nature  of  the  stone  will  allow." 

These  specifications  have  been  quoted  at  such  length  for  the 
reason  that  they  are  somewhat  out  of  the  ordinary  in  placing  prac- 
tically complete  control  over  the  concrete  work  in  the  hands  of 
the  engineer.  While  this  is  frequently  done  in  specifications  of 
different  form,  nevertheless  the  manner  in  which  it  is  accomplish- 
ed by  the  clauses  which  have  just  been  quoted,  tends  to  produce 
far  better  results  than  the  more  usual  method  of  specifying  the 
proportions  of  the  various  materials  entering  into  the  concrete 
and  requiring  the  contractor  to  furnish  them  all.  Where  a  con- 
tractor is  paid  a  lump  sum  for  the  construction  of  so  many  cubic 
yards  of  concrete  and  he  furnishes  the  cement,  he  is  exposed  to  the 
constant  temptation  to  use  as  little  cement  as  possible.  Moreover, 
unless  the  basis  of  payment  is  on  the  number  of  units  of  the  vari- 
ous classes  of  work  in  the  entire  undertaking,  there  is  a  natural 
tendency  on  the  part  of  the  contractor  to  do  as  little  work  as  is 
necessary  to  comply  with  the  letter  of  the  specifications.  Where 
he  is  paid  by  ihe  cubic  yard  of  excavation,  the  cubic  yard  of  con- 
crete, etc.,  the  more  work  the  engineer  calls  for  the  larger  will  be 
the  profit  on  the  entire  contract,  provided,  of  course,  the  con- 
tractor has  not  attempted  to  balance  his  bids  in  any  manner. 

A  combination  of  concrete  and  brick  is  sometimes  used  for 
the  lining  of  reservoirs,  an  example  of  such  work  being  shown 
in  Figure  45,  which  illustrates  the  construction  followed  in  1898 
in  a  reservoir  built  at  Lancaster,  Ohio,  from  the  plans  of  Mr.  John 
N.  Wolfe.  It  measures  100x200  feet  at  the  coping  level  and  is 
nearly  19  feet  in  depth  at  the  lowest  point.  The  reservoir  had  to 
be  built  on  a  soft  sandstone  formation  overlaid  by  clay,  and  a  low 
masonry  wall  was  constructed  in  order  to  secure  the  desired  sur- 
face elevation.  In  this  case  the  bottom  and  sides  of  the  basin 
were  covered  with  8  inches  of  concrete  on  which  a  course  of  brick 
was  laid  flatwise.  This  course  was  then  covered  with  1  inch  of 


230  WATER-WORKS  MANUAL. 

cement  and  lime  to  form  a  cushion  for  an  inside  lining  of  brick 
laid  edgewise  in  cement. 

ASPHALT-LINED   RESERVOIRS. 

The  use  of  asphalt  as  a  waterproofing  material  is  a  revival  of 
the  practice  in  vogue  centuries  ago.  Mr.  Rudolph  Hering  has 
pointed  out  that  this  material  was  used  at  Babylon  and  Ninevah 
about  4,000  years  ago  as  a  mortar  and  also  mixed  with  broken 
bricks  and  stone  to  form  a  concrete.  It  was  used  in  Egypt,  par- 
ticularly in  Memphis,  for  keeping  moisture  out  of  walls  and  base- 
ments. A  German  pamphlet  of  the  early  part  of  the  seventeenth 
century  describes  the  application  of  the  material  for  various  pur- 
poses, but  it  was  a  Greek  physician,  Dr.  Eyrinis,  who  first  brought 
rv:c^%. 


Concrete . 

'''(^f/^^' :--'-- ': -' '  '^^^A 
frace  Wall.. 


8  "Concrete 

_      r~?'/6£."f>".'  ''""*//, 

Soft   sandstone . 

FIGURE  45.— LANCASTER  BASIN. 

about  its  modern  use  for  waterproofing.  There  are  records  of 
cisterns  16  to  20  feet  in  diameter  which  were  laid  in  asphalt  and 
retained  water  successfully.  Count  Buffon,  the  French  naturalist, 
recommended  asphalt  as  a  mortar  in  building  a  large  basin  in  the 
Jardin  des  Plantes  in  Paris,  and  some  forty  years  later  he  wrote 
that  it  had  remained  perfectly  water-tight.  The  present  practice 
in  the  use  of  asphalt  in  America  may  be  best  illustrated,  since  it 
varies  considerably,  by  describing  a  number  of  recent  reservoirs 
in  which  it  has  been  used. 

The  Astoria,  Ore.,  reservoir,  built  under  the  direction  of  Mr.  A. 
L.  Adams,  M.  Am.  Soc.  C.  E.,  is  lined  on  the  bottom  with  con- 
crete and  asphalt.  The  concrete  wras  made  with  Portland  cement 
and  laid  in  20-foot  squares  6  inches  thick,  the  joints  between  the 


WATER-WORKS  MANUAL.  231 

squares  being  about  one-half  inch  thick.  The  joints  were  run  full 
of  asphalt  when  the  first  coat  of  the  latter  was  applied.  The  as- 
phalt was  of  the  Alcatraz  brand  of  the  L  and  L  L  L  grades.  When 
the  concrete  was  at  least  two  weeks  old  it  was  covered  with  the  L 
or  liquid  grade  and  then  followed  by  a  layer  of  the  L  L  L  or  hard 
grade.  Mr.  Adams  believes  that  any  advantage  possessed  by  a 
soft  coat  over  a  harder  one,  as  a  first  application,  is  more  fancied 
than  real.  "At  the  proper  temperature,  the  harder  grade  runs 
just  as  readily,  and  enters  all  crevices  just  as  surely  when  applied 
and  if  the  masonry  be  entirely  dry  and  clean,  and  preferably  a  lit- 
tle rough,  it  adheres  more  tenaciously  than  the  liquid.  The  only 
superiority  possessed  by  the  latter  as  a  first  coat  is  that  if  it  must 
be  applied  on  a  damp  surface,  it  will  adhere  where  the  other  will 
not." 

On  the  slopes  the  concrete  was  applied  in  sheets  10  feet  wide 
extending  up  and  down  the  slopes.  This  was  covered  with  a  layer 
of  the  L  L  L  asphalt,  and  paved  with  bricks  dipped  in  buckets  of 
hot  asphalt  and  placed  in  position  with  tongs.  A  final  finishing 
coat  of  asphalt  completed  the  work.  "When  this  lining  had  been 
exposed  to  the  rays  of  the  sun  for  a  considerable  time,  there  was  a 
\ery  noticeable  sliding  of  the  brick  on  the  slope,  and  a  consequent 
closing  up  of  the  joints,  crowding  out  the  asphalt  where  they  were 
thick  by  reason  of  the  asphalt  having  been  used  too  cold  on  days 
that  were  too  windy  to  permit  it  being  maintained  at  a  proper 
temperature.  As  a  consequence,  openings  were  produced  between 
the  brick  lining  and  the  wall  at  the  top  of  the  slope,  which  were 
filled  with  mastic.  The  footway  course  of  brick  was  prevented 
from  sliding  by  being  set  into  the  concrete  of  the  bottom  lining." 

Bock  asphalt  mastic  was  used  in  repairing  a  leaking  reservoir  at 
Coatesville,  Pa.,  a  work  for  which  Mr.  Alexander  Potter  was  the 
engineer.  In  this  case  an  old  brick  lining  was  taken  out  and  the 
clay  puddle  below  it  thoroughly  drained.  Brick  was  then  laid 
over  the  bottom  and  slopes,  and  painted  with  a  thin  coat  of  refined 
bitumen  and  benzine.  Over  this  the  asphalt  was  spread  1  inch 
thick  on  the  bottom  and  J  inch  on  the  sides.  It  was  placed  in 
two  layers  and  was  Neuchatel  mastic  heated  to  a  temperature  of  400 
degrees  Fahrenheit,  poured  on  the  surface  from  wooden  buckets 
and  smoothed  with  wooden  spatulas.  The  asphalt  is  carried  to 
the  head  of  the  slopes  and  18  inches  along  the  level  top,  where 
it  is  joined  with  a  concrete  gutter  15  inches  wide  and  4  inches 


233  WATER-WORKS  MANUAL. 

deep.  This  intercepts  the  water  which  might  seep  down  the 
slopes  below  the  lining  and  eventually  injure  them.  Mr.  Potter 
has  stated  that  the  use  of  a  somewhat  thinner  asphalt  lining  cov- 
ered with  tiles  about  1  inch  thick  might  prove  even  more  satisfac- 
tory than  the  plan  described.  These  tiles  should  be  dipped  in  re- 
fined bitumen  and  laid  before  the  asphalt  cools. 

Mr.  Gervaise  Purcell,  Assoc.  M.  Inst.  0.  E.,  has  used  an  asphaltic 
concrete  reservoir  lining  which  he  describes  as  a  mixture  of  25  per 
cent,  of  sand  and  75  per  cent,  of  gravel  in  100  pounds,  added  to  10 
pounds  of  California  asphalt  mastic.  The  sand  and  gravel  are 
heated  to  a  temperature  310  degrees  and  then  mixed  thoroughly 
with  the  asphalt,  which  has  been  heated  separately  to  a  tempera- 
ture of  280  to  300  degrees.  This  concrete  is  tamped  into  place, 
and  then  smoothed  with  a  hot  roller  to  prepare  it  for  a  surface 
coat,  prepared  according  to  the  following  formula:  "To  100  pounds 
of  hard  asphalt  are  added  3  pounds  of  liquid  asphalt  capable  of 
standing  a  300-degree  flash  test  with  specific  gravity  under  10  de- 
grees Beaume;  the  whole  is  heated  to  400  degrees  Fahr.,  and  the 
temper  maintained  by  the  addition  of  small  quantities  of  liquid 
asphalt  from  time  to  time  as  the  more  volatile  portion  evaporates; 
to  this  is  added  between  10  and  12  per  cent,  of  powdered  carbonate 
of  lime  or  sulphate  of  lime,  according  to  the  peculiarities  of  the 
asphalt."  This  is  poured  over  the  surface  and  rubbed  smooth 
with  a  heated  iron  tool  2  inches  in  diameter,  8  inches  long  and 
mounted  in  a  long  handle. 

The  reservoir  of  the  La  Grande,  Ore.,  water-works  was  built  in 
1892  from  plans  prepared  by  Messrs.  Adams  &  Gemmell.  It  is 
an  oval  basin  of  1,000,000  gallons  capacity,  partly  in  excavation 
and  partly  in  embankment,  and  is  lined  with  a  course  of  brick 
covered  lay  a  f-inch  coat  of  asphalt.  After  the  slopes  were  thor- 
oughly rammed,  the  bricks  were  laid  on  edge  and  their  joints  filled 
with  clean  sand.  The  asphalt  was  cooked  at  the  site  of  the  work, 
its  proportions  being  one  part  by  weight  of  coal  tar  to  eight  or  nine 
parts  of  California  rock  asphaltum.  Between  1,700  and  1,800 
pounds  of  asphalt  were  cooked  at  a  time,  the  process  lasting  five 
or  six  hours,  or  until  the  mass  became  liquid  and  uniform.  It 
was  spread  over  the  bricks  by  means  of  shovels  and  brooms,  two 
layers  being  necessary  to  make  up  the  requisite  thickness.  The 
total  cost  of  the  lining,  brick  work,  asphalt  and  labor,  was  about 
12.5  cents  per  square  yard. 


WATER-WORKS  MANUAL.  233 

Another  reservoir,  of  about  420,000  gallons  capacity,  built  by 
the  same  engineers  at  Waitsburg,  Wash.,  was  likewise  partly  in 
excavation  and  partly  in  embankment  and  dependent  for  tight- 
ness on  an  asphalt  lining.  The  earth  was  light  and  ashy,  and 
\\as  difficult  to  work  into  a  bank.  The  lining  was  put  on  in  two 
layers,  one  of  paving  asphalt  1^  inches  thick,  and  the  outer  one  of 
pure  asphaltum  about  ^-inch  thick.  The  asphalt  was  mixed  in 
the  proportions  of  eight  parts  rock  asphaltum  to  two  parts  Las 
Conchas  asphaltum.  These  ingredients  were  cooked  from  ten  to 
twelve  hours,  and  then  mixed  with  sand  in  the  proportion  of  one" 
part  by  weight  of  asphaltum  to  five  parts  of  hot  sand.  The  asphalt 
\\as  laid  in  vertical  strips,  the  edges  of  the  strips  being  painted 
with  pure  asphaltum  before  new  material  was  laid  against  them. 
On  account  of  a  leak  in  one  of  the  pipes,  the  earth  below  a  part  of 
the  lining  was  undermined  a  few  days  after  water  was  turned  into 
the  reservoir.  The  water  pressure  broke  the  lining,  but  not  until 
the  asphalt  had  been  dished  4  inches  in  an  area  perhaps  20  inches 
in  diameter.  The  cost  of  this  lining  was  the  same  as  that  at  the 
La  Grande  reservoir. 

A  true  asphalt  concrete  has  been  recommended  by  Mr.  R.  B. 
Stanton,  M.  Am.  Soc.  C.  E.,  for  reservoir  linings  under  certain  cir- 
cumstances. The  concrete  used  by  him  on  a  reservoir  for  mining 
purposes  consisted  of  porphyry  broken  to  2  inches  and  less  in  size, 
with  all  the  small  stone  and  dust  left  in  and  enough  fine  material 
added  to  form  a  perfect  concrete  when  bound  together  by  the 
asphalt.  The  asphalt  was  formed  by  four  parts  of  refined  Cali- 
fornia asphaltum  and  one  part  of  crude  petroleum,  cooked  in  a 
paving  kettle  until  pasty  and  then  poured  over  the  rock,  which  had 
meanwhile  been  heated  in  another  kettle.  This  concrete  was  put 
on  in  a  layer  4  inches  thick  in  strips  from  4  to  6  feet  in  width,  the 
old  edges  being  coated  with  hot  paste  before  new  material  was  laid 
against  them.  When  the  lining  was  finished  it  was  painted  with 
hot  asphaltum  paste  mixed  in  the  same  proportions  as  that  for  the 
concrete,  but  boiled  a  much  longer  time,  until  when  cold  it  was 
hard  and  brittle,  breaking  under  the  hammer  like  glass,  yet  tough, 
elastic  and  pliable  with  the  least  warmth.  This  painting  was  done 
while  the  paste  was  very  hot  and  could  be  ironed  down  with  hot 
irons.  Its  thickness  should  not  exceed  J  inch.  This  lining  gave 
excellent  satisfaction  in  difficult  service. 

Another  method  of  using  asphalt  recommended  by  Mr.  L.  J. 


234  WATER-WORKS  MANUAL. 

Le"Oente,  M.  Am.  Soc.  C.  E.,  for  steep  slopes  is  the  following: 
The  slope  of  wall  of  masonry  is  first  coated  with  asphalt  heated 
only  enough  to  make  it  liquid,  which  has  great  penetrating  and 
adhesive  properties,  but  is  lacking  in  sun-proof  qualities.  Then 
a  layer  of  ordinary  heavy  burlap  is  stretched  tight  and  pressed  into 
the  asphalt  paint.  The  final  step  is  to  put  on  a  boiling  hot  coat  of 
"hard"  asphalt,  which  constitutes  the  weather  surface  and  is  hard, 
tough  and  admirably  resistant  to  the  hot  summer  sun.  "Wherpver 
this  lining  has  been  used,  no  signs  of  creeping  have  developed 
even  on  smooth  vertical  faces.  Hard  asphalt  paint  is  lacking  in 
adhesive  qualities,  and  consequently  cannot  be  placed  directly  on 
the- elopes."  This  lining  is  recommended  for  slopes  steeper  than 
1  on  1.5;  for  flatter  slopes  Mr.  Le  Conte  advises  the  use  of  asphalt 
mortar  or  asphalt  cement. 

The  latest  example  of  an  asphalt-lined  reservoir  at  the  time  of 
the  writing  of  this  chapter  is  afforded  by  a  1,600,000-gallon  basin 
constructed  at  Black  Hawk,  Colo.,  under  the  direction  of  Mr. 
Walter  Pearl.  Most  of  this  basin  is  in  excavation,  but  at  some 
places  the  slopes  have  been  carried  upward  by  rubble  masonry 
walls  backed  with  earth.  The  lining  is  brick  dipped  in  Pacific 
asphalt  paving  cement.  Most  of  the  brick  used  on  the  bottom  are 
>hat  is  known  as  machine  made,  medium  hard  burned,  sand  brick; 
those  used  on  the  sides  are  terra-cotta  brick  of  the  usual  building 
size.  The  side  slopes  are  four  on  one.  At  ]east  one-third  of  the 
excavation  on  the  slopes  was  left  in  such  bad  condition  by  blasting 
that  it  had  to  be  lined  with  rubble  masonry  laid  in  Milwaukee 
cement  before  the  brick  could  be  placed.  The  bottom  of  the  reser- 
voir was  covered  with  a  cushion  of  sand  from  J  to  3  inches  thick, 
varying  according  to  the  inequalities  of  the  surface  of  the  excava- 
tion. The  brick  laid  on  it  were  dipped  for  half  their  width  in 
hot  asphalt,  and  after  they  were  placed  on  edge  on  the  sand  the 
joints  and  cracks  were  filled  with  asphalt,  which  material  was  also 
swept  over  the  surface  with  brooms. 

Around  the  edge  of  the  bottom  lining  a  bed  was  made  to  fur- 
nish a  footing  for  the  slope  lining.  This  bed  was  a  mixture  of 
about  20  per  cent,  of  asphaltic  cement  and  80  per  cent,  of  sand.  Be- 
fore the  brick  were  laid  anchor  bolts  were  placed  in  the  walls  so  that 
the  brick  could  be  held  from  falling  inward  after  they  were  laid. 
The  brick  for  the  sides  were  entirely  dipped  in  asphalt  except  for 
the  small  space  where  they  were  held.  After  they  were  placed 


WA  TER-  WORKS  MAN  UAL.  235 

they  received  a  coating  of  asphalt.  The  brick  were  laid  flat  mak- 
ing a  wall  4  inches  thick,  and  sand  or  concrete  was  filled  in  behind 
the  wall  as  fast  as  the  brick  were  laid.  Unless  this  was  done,  the 
sunshine  had  a  tendency  to  keep  the  asphalt  so  warm  that  the  wall 
slid  in  some  places  and  had  to  be  rebuilt.  When  the  brick  were 
laid,  it  was  found  that  there  were  a  number  of  open  joints,  so  be- 
fore the  final  coat  of  asphalt,  was  brushed  over  the  surface,  these 
joints  were  raked  out  and  pointed  with  a  rich  mixture  of  asphaltic 
cement  and  sand  much  as  a  masonry  wall  is  pointed  with  Portland 
cement. 

STANDriPES  AND  WATER  TANKS. 

Standpipes  and  water  tanks  are  particularly  applicable  in  two 
situations;  one  is  where  the  surrounding  country  is  so  level  as  to 
afford  no  elevation  suitable  for  a  reservoir,  and  the  other  is  where 
the  amount  of  water  to  be  stored  is  so  small  that  the  construction 
of  a  masonry  basin  is  more  expensive  than  the  building  of  a 
suitable  tank. 

A  standpipe  is  merely  a  large  shell  of  wrought  iron  or  steel 
plates  put  together  much  after  the  fashion  of  a  boiler.  The  fun- 
damental principles  on  which  the  design  should  be  based  are 
comparatively  simple,  and  yet  they  have  been  violated  frequently, 
and  the  last  25  years  present  a  discreditable  record  of  standpipe 
failures.  A  lank  of  this  sort  is  subjected  to  wind  pressure  tend- 
ing to  buckle  it,  especially  when  empty,  as  was  actually  the  case 
in  a  well-built  structure  near  Providence.  When  the  pipe  is 
filled  with  water,  it  is  subjected  to  a  bursting  strain  in  the  metal 
and  in  the  vertical  joints,  due  to  the  pressure  of  the  water  within 
it.  The  wind  pressure,  in  addition  to  its  tendency  to  force  in  the 
plates  on  the  side  against  which  the  wind  blows,  also  strains  the 
horizontal  joints.  A  consideration  of  these  strains  is  not  a  difficult 
problem.  The  stress  in  the  metal  tending  to  burst  the  pipe  at 
any  elevation  may  be  found  by  computing  the  hydrostatic  pressure 
of  the  water  at  that  point,  multiplying  this  pressure  expressed  in 
pounds  per  square  inch  by  the  diameter  in  inches  of  the  stand- 
pipe,  and  dividing  the  product  by  twice  the  thickness  in  inches 
of  the  plate  at  that  elevation.  The  result  will  be  the  stress  per 
square  inch  due  to  the  water  at  that  elevation.  The  wind 
pressure  is  equal  to  about  half  the  wind  pressure  on  a  flat  surface 
of  the  same  height  and  diameter  as  the  standpipe;  if  it  is  assumed 
that  the  wind  presses  against  a  flat  surface  at  about  45  pounds 


256  WATER-WORKS  MALUAL. 

per  square  foot,  the  pressure  on  a  standpipe,  expressed  in  pounds 
per  square  foot,  will  be  45  times  the  height  of  the  pipe  in  feet 
multiplied  by  one-half  its  diameter,  also  expressed  in  feet. 

It  is  now  the  established  practice  to  use  steel  plates  for  such 
pipes,  although  for  many  years  a  number  of  prominent  engineers 
refused  to  employ  anything  but  a  high  grade  of  wrought  iron.  If 
steel  is  used  it  should  be  soft,  open-hearth  metal  having  an  ulti- 
mate tensile  strength  of  55,000  to  62,000  pounds  per  square  inch, 
with  an  elastic  limit  of  half  the  ultimate  strength.  The  mini- 
mum elongation  in  test  pieces  8  inches  in  length  should  range 
from  about  22  per  cent,  for  plates  less  than  f-inch  thick  to  about 
26  per  cent,  for  plates  more  than  |-inch  thick.  The  cold-bend 
test  should  require  the  steel  to  be  bent  flat  upon  itself  without 
fracture,  except  in  the  case  of  plates  more  than  half  an  inch  thick, 
when  the  bending  should  be  done  around  a  mandrel  of  a  diameter 
equal  to  the  thickness  of  the  plate.  It  is  probable  that  the  best 
results  would  be  obtained  by  requiring  the  sheared  edges  of  the 
plates  to  be  planed  before  the  holes  are  punched,  and  to  ream  the 
holes  before  the  plates  are  bent.  This  has  never  been  done,  so 
far  as  the  writer  knows,  but  it  would  certainly  tend  to  prevent  the 
use  of  plates  having  any  defects  along  the  edges,  which  weaken 
the  standpipe  in  its  most  vulnerable  point. 

The  best  current  practice  in  workmanship  at  the  time  of  writing 
is  shown  by  the  following  extracts  from  specifications  prepared  in 
1897  by  Mr.  Nicholas  S.  Hill,  Jr.,  at  that  time  chief  engineer  of 
the  Baltimore  water-works:  "The  plates  and  angles  shall  be 
shaped  to  the  proper  curvature  by  cold  rolling.  No  heating  and 
hammering  shall  be  allowed  for  straightening  or  curving.  The 
work  shall  be  carefully  and  accurately  laid  out  in  the  shop,  and 
the  rivet  holes  punched  with  a  center  punch,  sharp  and  in  perfect 
order,  from  the  surface  to  be  in  contact.  The  diameter  of  the 
punch  shall  not  exceed  that  of  the  rivet  by  more  than  1-16  inch, 
and  the  diameter  of  the  die  shall  in  no  case  exceed  that  of  the 
punch  by  more  than  1-16  inch.  Rivet  holes  in  plates  having  a 
thickness  of  f -inch  and  over  shall  be  drilled  and  sharp  edges  shall 
be  trimmed.  All  calking  edges  shall  be  planed  to  a  proper  bevel. 
All  parts  must  be  adjusted  to  a  perfect  fit  and  properly  marked 
before  leaving  the  shop.  In  assembling  the  work  the  rivet  holes 
shall  match  so  that  hot  rivets  may  be  inserted  without  the  use  of 
a  hammer.  Drifting  is  prohibited.  Eccentric  holes,  if  any,  must 


WATER-WORKS  MANUAL.  237 

be  reamed,  and  if  required  larger  size  rivets  shall  be  used  in  such 
holes.  The  best  grade  of  soft  charcoal  iron  rivets  in  the  market 
shall  be  used.  Sufficient  stock  must  be  provided  in  the  rivets  to 
completely  fill  the  holes  and  make  a  full  head.  The  rivets  shall 
be  driven  at  such  a  heat  as  will  admit  of  their  being  finished  in 
good  form,  with  a  button  set  before  the  rivet  has  cooled  to  a 
critical  point.  As  often  as  may  be  deemed  advisable  for  the  pur- 
pose of  testing  the  work,  rivets  shall  be  cut  out  at  the  direction 
of  the  inspector.  The  quality  of  the  rivet  metal  and  of  the  work- 
manship shall  be  such  that  the  fracture  of  the  rivet  so  removed 
at  random  shall  show  a  good,  tough,  fibrous  structure  without  any 
crystalline  appearance,  and  there  shall  be  no  evidence  of  brittle- 
ness.  Loose  rivets  must  be  promptly  replaced,  no  rivet  calking 
being  permitted.  All  seams  must  be  calked  thoroughly  tight  with 
a  round-nose  calking  tool  by  workmen  of  acceptable  skill.  Great 
care  must  be  taken  not  to  injure  the  under  plate."  Good  paint- 
ing is,  of  course,  insisted  on. 

The  method  of  computing  the  strength  of  riveted  joints  is  too 
far  removed  from  the  scope  of  this  book  for  discussion  here;  it 
is  explained  in  Trautwine's  Pocket-Book,  which,  as  before  stated, 
should  be  in  the  office  of  every  water-works.  The  riveting  never 
develops  the  full  strength  of  the  plates,  as  is  shown  by  the  follow- 
ing table  prepared  by  Mr.  Freeman  C.  Coffin: 

THE  STRENGTH  OF  RIVETED  JOINTS— THE  LETTERS  REFER  TO  FIGURE  46. 


Single  rivet. 
Double 


Triple  . . '. . 


Rivets. 


Q 

F 


54.5 
52.5 
66.0 
66.0 
64.7 
63  0 
63.0 
62.0 
61.0 
60.0 
61.0 
59.3 
59.0 
59.0 
70.0 


It  is  customary  to  use  a  factor  of  safety  of  five  in  figuring  the 
metal  of  standpipes,  which  is  equivalent  to  a  factor  of  safety  of 


238  WA  TER-  WORKS  MANUAL. 

about  three  in  the  joints.  As  the  weakest  point  of  a  structure 
determines  its  strength,  it  is  evident  that  every  precaution  should 
be  taken  with  the  riveting.  Since  about  1893  the  vertical  seams 
have  frequently  been  made  butt  joints  with  straps  inside  and  out- 
side. This  is  a  decided  advantage  in  securing  good  workman- 
ship where  the  plates  are  over  half  an  inch  in  thickness.  Butt 
•joints  are  always  used  in  the  bottom  (horizontal)  plates.  Machine 
work  gives  better  results  than  hand  riveting,  and  the  rivets  should 
be  heated  on  an  elevated  stage  near  the  work.  The  best  practice 
is  to  make  the  horizontal  courses  of  plates  alternate  inside  and 
outside,  rather  than  have  each  course  slightly  tapering. 

The  top  plates  of  an  exposed  standpipe  are  not  usually  less  than 
i-inch  thick,  although  thinner  metal  will  withstand  the  bursting 
pressure.  The  additional  thickness  gives  stiffness  to  the  pipe  and 


O    O 


FIGURE  46.— RIVET  DIAGRAM. 

makes  the  calking  comparatively  easy.  The  top  of  the  pipe  should 
be  strengthened  by  a  ring  of  3x3-inch  or  larger  angle  iron  riveted 
outside  the  rim.  The  plates  of  the  bottom  are  subjected  to 
little  stress  but  have  to  be  made  ibout  three-fourths  the  thick- 
ness of  the  lowest  vertical  course  in  order  to  be  calked  well  and 
to  resist  corrosion  on  their  lower  surface.  The  writer  believes  the 
bottom  plates  should  project  beyond  the  lowest  ring  course  about 
6  inches  so  that  a  6x6-inch  angle  can  be  double-riveted  to  both 
around  the  outside  of  the  tank.  The  horizontal  leg  of  this  angle 
can  be  bolted  to  the  masonry  foundation  at  as  many  points  as  seems 
necessary  so  as  to  avoid  the  use  of  brackets  riveted  to  the  side 
plates  and  anchored  by  rods  to  the  foundation.  These  brackets 


WATER-WORKS  MANUAL.  *3t 

are  used  for  preventing  the  overturning  of  the  tank  by  wind 
pressure  when  it  is  empty,  but  they  weaken  the  side  plates  and  the 
bottom  outside  angle  will  answer  the  purpose  just  as  well  except 
when  the  tank  is  tall  and  slender,  in  which  case  it  must  be  guyed 
by  stays  running  to  well-set  posts. 

The  masonry  foundation  of  a  standpipe  deserves  particular  at- 
tention, as  several  failures  of  these  structures  have  shown.  Con- 
crete can  generally  be  employed  to  advantage,  but  no  matter  what 
material  is  used  it  must  be  carried  down  far  enough  and  spread 
wide  enough  to  ensure  absolute  freedom  from  settlement  of  any 
Bort.  The  bottom  plates  of  the  tank  are  generally  put  to- 
gether on  supports  a  few  feet  above  the  top  of  the  masonry,  which 
is  then  covered  to  a  depth  of  2  inches  with  a  dry  mixture  of  equal 


2"5and  and  Cement- 


Circular  Plate. 


Bottom  Plate,  of  Tank. 


FIGURE  47. — INLET  TO  STANDPIPE, 

parts  of  cement  and  sand.  This  affords  a  bed  on  which  the  bottom 
is  lowered  and  makes  it  certain  that  the  pressure  on  the  masonry 
is  uniform  and  the  plates  subjected  to  no  excessive  localized 
strains. 

The  pipe  through  which  the  water  enters  the  standpipe  is  now 
generally  a  branch  from  the  force  main  and  serves  also  as  the  dis- 
charge main,  the  water  level  in  the  tank  rising  and  falling  as  the 
demand  for  water  fluctuates  one  way  or  the  other  from  the  uni- 
form delivery  of  the  pumps.  The  pipe  is  carried  in  an  arched 
passageway  through  the  masonry  until  it  is  about  6  feet  inside  the 
line  of  the  shell  and  ends  in  a  special  quarter  bend  having  a  flange 
by  which  it  can  be  anchored  to  a  block  of  masonry.  From  this 
bend  a  pipe  rises  vertically  and  enters  the  tank  by  some  such  ar- 
rangement as  is  shown  in  Figure  47  or  by  a  stuffing  box  and  gland 
of  the  type  used  to  pack  the  piston  rods  of  steam  cylinders.  The 
overflow  pipe  should  never  be  placed  inside  a  tank  in  which  ice 


24G  WATER-WORKS  MANUAL. 

wi'fi  torm,  for  it  will  be  ruined  sooner  or  later.  A  telemeter.  Cu; 
which  there  are  several  types  on  the  market,  can  be  purchased  at 
a  low  cost,  and  its  use  will  enable  the  engineer  of  the  pumping 
Nation  to  slow  down  his  pumps  whenever  the  standpipe  is  fuii. 
If  an  overflow  pipe  must  be  used,  it  should  be  placed  outside  the 
tank,  as  has  been  done  in  many  instances,  particularly  when  the 
tank  is  enclosed. 

If  the  standpipe  is  on  a  plain,  it  is  customary  to  provide  the 
pipe  connecting  it  with  the  force  main  with  a  valve  which  can  be 
closed  from  the  pumping  station  when  a  fire  alarm  is  sounded. 
If  this  is  not  done,  it  is  impossible  to  put  sufficient  pressure  on  the 
mains  to  obtain  good  fire  streams.  If  the  standpipe  is  situated 
on  an  elevation  which,  in  itself,  affords  ample  fire  pressure,  no  such 
valve  is  needed.  There  are  a  number  of  such  devices  on  the  mar- 
ket, some  worked  by  electricity,  some  by  water  pressure,  and  some 
automatically  by  the  pressure  in  the  pipes.  A  pressure-regulator 
such  as  is  used  between  high-service  and  low-service  street  mains 
might  be  arranged  to  do  this  work,  although  the  writer  has  no  per- 
sonal knowledge  of  such  an  installation. 

A  peculiar  form  of  standpipe  was  built  about  1890  at  Fort  Smith, 
Ark.,  from  the  plans  of  M.  M.  Tidd.  It  is  30  feet  in  diameter  and 
100  feet  high.  The  pipe  which  connects  it  with  the  force  main  is 
16  inches  in  diameter  and  branches  just  outside  the  masonry  foun- 
dation into  two  pipes.  One  of  these  ends  in  a  riser  terminating  in 
the  bottom  of  the  tank  and  is  provided  with  a  check  valve  which 
permits  only  a  flow  from  the  tank.  The  second  branch  is  con- 
nected with  a  16-inch  pipe  rising  vertically  through  the  center  of 
the  stand-pipe  to  an  elevation  of  6  feet  above  its  top.  This  verti- 
cal pipe  is  guyed  to  the  shell  of  the  tank  by  half -inch  wire  rope 
with  turnbuckle  adjustments.  The  small  pipe  is  filled  by  the  first 
strokes  of  the  pump  and  gives  a  full  head  to  the  supply  unless  the 
draft  exceeds  the  delivery  of  the  pump,  in  which  improbable  event 
the  supply  would  be  augmented  by  the  water  stored  in  the  stand- 
pipe,  the  height  of  which  would  govern  the  pressure,  as  it  does 
whenever  the  pump  is  not  working.  The  standpipe  can  be  filled 
only  through  water  overflowing  the  top  of  the  center  pipe,  and  the 
considerable  distance  that  the  overflow  falls  retards  the  formation 
of  ice. 

By  using  a  winding  stairway  and  a  conical  roof  it  is  frequently 
possible  to  make  an  uncased  standpipe  a  fairly  pleasing  object 


WATER-WORKS  MANUAL, 


241 


The  tank  shown  in  Figure  48  was  built  a  number  of  years  ago  for 
the  Des  Moines  Water  Company  from  the  plans  of  Mr.  Chester  B 
Davis.     It  is  30  feet  in  diameter,  100  feet  high  and  furnished  with 
a  balcony  and  roof  which  relieves  the  hard  lines  of  the  tower.    The 


<=O. 

FIGURE  48.— THE  DES  MOINES  STANDPIPE. 

roof  is  covered  with  unpainted  No.  22  sheet  copper.  The  floor  is 
supported  by  iron  beams  and  consists  of  a  2-inch  bottom  course 
of  pine  finished  with  a  course  of  selected  1-inch  hard  pine.  The 
ceiling  of  the  roof  is  No.  20  corrugated  iron.  Another  attractive 


242 


WATER-WORKS  MANUAL. 


FIGURE  49.— WATER  TANK  AT  NORWOOD,  OHIO. 


WATER- WORKS  MANUAL.  243 

tank,  shown  in  Figure  49,  was  built  at  Norwood,  Ohio,  from  the 
plans  of  Mr.  G.  Bouscaren. 

It  is  sometimes  desirable,  occasionally  even  necessary,  to  enclose 
the  standpipe  in  masonry  to  protect  it  from  wind  pressure  and  the 
cold.  When  this  is  done  very  attractive  architectural  effects  can 
be  produced,  as  is  shown  by  completed  structures  and  the  results 
of  a  prize  competition  instituted  by  "The  Engineering  Record"  in 
1890.  The  best  of  the  plans  received  in  that  competition  are  pub- 


FIGURE  50  -  LAWRENCE  WATER  TOWER. 

lished  by  the  journal  mentioned.  The  masonry  tower  at  Law- 
rence, Mass.,  is  shown  in  Figure  50.  The  first  27  feet  of  the 
masonry  above  ground  is  broken  granite  ashlar,  and  the  remainder 
is  brick  with  granite  trimmings.  The  main  tower  is  octagonal  in 
plan  and  there  is  also  a  projecting  circular  tower  of  6  feet  inside 
diameter  in  which  an  iron  stairway  winds  upward  to  the  balcony. 
The  tank  is  30  feet  in  diameter  and  102£  feet  high.  The  floor  of 
the  balcony  is  about  107  feet  above  ground,  and  the  point  of  the 
roof  about  157  feet. 


244 


WATER-WORKS  MANUAL. 


Where  a  town  is  located  in  a  flat  country  it  is  self-evident  that  the 
water  in  the  lower  part  of  a  tank  is  of  no  use  whatever.,  as  a  head  of 
50  feet  is  needed  to  give  pressure  amounting  to  anything.  This  fact 
has  led  to  the  erection  of  tanks  on  the  top  of  metal  towers  or  ma- 
sonry shafts,  and  such  structures  often  prove  more  economical 
than  a  standpipe.  The  construction  of  the  tank  itself  offers  no 
features  of  special  interest  save  that  the  bottom  is  usually  made 
conical  when  steel  framing  is  used  for  a  support,  unless  the 

,12  Ho  Us,  each  % 


B 


FIGURE  51.— DETAILS  OF  FAIRHAVEN  STANDPIPE. 


capacity  of  the  tank  is  so  small  that  it  can  be  satisfactorily  held  an 
a  platform  resting  on  girders.  If  the  bottom  is  conical,  the  supply 
pipe  enters  at  its  lowest  point  through  a  stuffing-box,  as  shown 
in  Figure  51,  which  also  gives  details  of  the  method  of  connecting 
the  side  and  bottom  plates  and  supporting  the  entire  weight  on  a 
plate  girder.  These  details  are  from  a  Massachusetts  water  tower 
designed  in  the  office  of  the  late  M.  M.  Tidd  by  Mr.  Freeman  C. 
Coffin. 

The  design  of  the  steel  work  for  such  a  tower  calls  for  an  ac- 


WATER-WORKS  MANUAL.  345 

quaintance  with  subjects  entirely  foreign  to  this  book,  but  it  is 
believed  that  the  detail  drawings  in  Figure  52  will  prove  of  value 
to  many  of  its  readers.  This  tank  was  designed  by  Mr.  Edward 
Flad  for  the  water-works  in  Laredo,  Tex,,  and  is  one  of  the  few 
in  this  country  with  a  curved  bottom,  although  the  pattern  is  a 
favorite  abroad. 

The  water  tower  at  Oberlin,  Ohio,  built  from  the  plans  of  Mr. 
W.  B.  Gerrish,  affords  an  instance  of  a  masonry  pedestal  for  a  steel 
tank.  It  consists  of  a  stone  base  40  feet  high  above  the  ground, 
on  which  rests  a  steel  tank  35  feet  high  and  18  feet  in  diameter. 
The  concrete  bottom  course  of  the  foundation  of  the  base  is  2  feet 
thick,  and  forms  a  ring  9  feet  wide  on  which  are  four  courses  of 
rubble  masonry  having  a  total  depth  of  6^  feet,  capped  by  a  water 
table  6  inches  thick.  On  this  foundation  the  base  was  built,  con- 
sisting of  a  light-colored  sandstone  tower  22  feet  in  exterior  di- 
ameter at  the  bottom  and  20  feet  just  below  the  coping.  The 
walls  are  3  feet  thick  at  the  bottom  and  2  feet  at  the  top,  the 
batter  being  entirely  on  the  exterior.  The  interior  of  the  base  is 
divided  into  three  stories,  two  of  14  feet  and  a  top  one  of  10  feet. 
Entrance  to  the  tower  is  through  a  doorway  measuring  3x7  feet, 
with  a  semi-circular  glazed  transom  above  it.  The  second  floor 
is  lighted  by  a  round  window  3  feet  in  diameter,  and  on  the  top 
floor  there  is  a  door  furnishing  access  to  a  light  iron  balcony  from 
which  a  ladder  leads  to  the  tank  above.  All  masonry  is  quarry 
faced  ashlar  in  regular  courses,  decreasing  from  about  24  inches 
at  the  bottom  to  10  inches  at  the  top.  At  least  one-fourth  of  the 
masonry  was  required  to  be  headers  and  at  least  four  stones  in 
each  course  had  to  extend  entirely  through  the  wall.  The  headers 
had  to  be  two-thirds  the  thickness  of  the  wall,  and  the  stretchers 
had  to  be  twice  their  height  and  of  a  width  equal  to  their  height 
at  least. 

EQUIVALENTS  FOR  STANDPIPES. 

The  purpose  of  a  service  reservoir  or  standpipe  is  two-fold;  to 
furnish  storage  for  a  certain  volume  of  water,  and  to  furnish  a 
head  or  pressure.  Where  no  such  works  are  built,  the  pumping 
plant  must  be  run  continuously  at  fluctuating  rates  and  is  subject 
to  severe  strains  whenever  hydrants  are  turned  on  or  off  or  a  pipe 
breaks.  Several  devices  have  been  employed  to  remedy  such 
shocks  and  there  is  a  special  system  of  works  which  provides  a 
substitute  for  all  functions  of  the  standpipe. 


246 


WATER-WORKS  MANUAL, 


FIGURE  52  —LAREDO  WATER-TOWER. 


WATER-WORKS  MANUAL. 


247 


In  the.  smallest  direct-pumping  European  water-works  an  ac- 
cumulator is  occasionally  employed.  This  is  a  strong  vertical  pipe 
with  a  stuffing-box  at  the  top  through  which  a  heavily  weighted 


Elevation  of  Column  showin 
Brackets  for  Branch  Columns. 


Wrought  Iron  Pipe 
not  less  thanj."  Metal.  l6"Diam, 

Straps.  Each  in  4  \ 


,4"*4"L 
12.5* 


Plan  of  Branch  Column 
and  Connections. 


Base  of  Column. 

FIGURE  52A.— DETAILS  OP  LAREDO  TOWER. 


ram  passes.     The  pipe  is  connected  with  the  force  main,  and  any 
marked  fluctuations  of  pressure  in  the  latter  are  prevented  by  the 


248  WATER-WORKS  MANUAL. 

movement  of  the  ram.  It  is  questionable  if  such  an  arrangement 
\vould  prove  satisfactory  in  more  than  a  very  few  cases  in  this 
country. 

Large  air  chambers  on  the  force  main  are  frequently  used  in 
Germany  as  a  substitute  for  the  pressure-equalizing  function  of 
the  standpipe.  In  Herr  Lueger's  "Wasserversorgung  der  Staedte" 
the  following  outline  of  their  theory  is  given.  If  V  is  the  volume 
of  air  in  an  air  chamber  when  the  delivery  of  the  pumps  just  equals 
the  demand  for  water  and  P  is  the  pressure  of  the  air  at  this  mo- 
ment, then,  if  the  demand  for  water  varies  by  an  amount,  q,  the 
air  in  the  chamber  has  a  new  volume,  v,  corresponding  to  a 
changed  pressure,  p.  Hence: 

v  —  V  =  q  pv  =  PV 

The  second  equation  is  Mariotte's  law.  Combining  the  equa- 
tions gives 

P=pvT^ 

It  is  evident  that  the  more  the  value  of  the  second  fact  on  the 
right-hand  side  approaches  unity,  the  nearer  become  p  and  P. 
These  pressures  correspond,  however,  to  heads  of  h  and  H  feet  in 
the  force  main  and  by  substituting  these  values  and  altering  the 
form  of  the  equation  the  following  relation  will  be  obtained: 

v-    -9L*_ 

-    H-h 

By  assuming  various  values  of  q  and  h  the  size  of  the  air  cham- 
ber can  be  easily  determined  for  any  given  conditions. 

One  of  the  most  interesting  applications  of  these  chambers 
with  which  the  writer  is  acquainted  was  made  many  years  ago  in 
Augsburg.  The  engine  room  floor  is  about  33  feet  below  the 
highest  street  surface  in  the  city,  where  a  head  of  nearly  100  feet 
was  desired.  Between  these  points  the  loss  of  head  due  to  fric- 
tion was  about  41  feet,  so  that  the  total  dynamic  head  at  the  pump- 
ing station  had  to  be  about  174  feet.  To  elevate  a  tank  to  such 
a  height  would  be  very  costly,  so  four  air  chambers  were  employed 
instead.  Each  is  32.8  feet  high,  4.9  feet  in  diameter  and  has  a 
capacity  of  nearly  800  cubic  feet.  The  manner  in  which  they 
are  charged  with  air  the  writer  has  never  succeeded  in  learning. 

The  air  chamber  of  the  Madison,  Wis.,  works  was  designed  by 
Mr.  Edwin  Reynolds  to  prevent  the  severe  shocks  on  the  pump- 
ing machinery  forcing  water  directly  into  the  mains,  which  were 
due  to  the  sudden  closing  of  hydrants.  These  water  rams  some- 


WATER-WORKS    MANUAL.  249 

times  amounted  to  40  pounds.  The  chamber  is  5  feet  in  di- 
ameter, 20  feet  high,  and  built  of  steel  plates,  and  is  on  the  main 
discharge  pipe.  At  ordinary  pressures  it  is  filled  with  air.  Dur- 
ing a  rise  in  pressure  from  75  pounds,  the  ordinary  amount,  to 
150  pounds  for  fire  service,  the  chamber  takes  in  about  200  cubic 
feet  of  water,  and  the  expansive  force  of  the  compressed  air  prompt- 
ly returns  this  water  to  the  main  in  case  of  any  sudden  demand.  In 
case  a  hydrant  is  suddenly  closed,  the  chamber  is  again  able  to 
take  up  the  excess  of  water  while  the  engines  are  slowing  down. 
A  2-inch  feed  pipe  and  a  small  air  pipe  run  to  a  small  receiver 
which  has  a  set  of  valves  so  designed  that  it  can  be  relieved  of  the 
pressure  in  the  air  chamber  and  the  water  exhausted  from  it,  when 
it  will  fill  with  air.  By  changing  the  position  of  a  lever,  the  air 
contained  in  this  reservoir  will  then  be  forced  into  the  air  chamber 
by  the  water  flowing  from  the  latter  into  the  former.  This  ap- 
paratus has  been  very  satisfactory. 

The  experience  of  the  Wyoming,  Ohio,  water- works  in  1898 
shows  the  value  of  such  a  chamber  even  on  small  plants.  The 
pipes  of  these  works  were  originally  laid  in  an  inferior  manner, 
^hich  resulted  in  much  annoyance  and  expense  due  to  the  fre- 
quent blowing  out  of  the  joints,  especially  on  the  10-inch  force 
main  and  the  lateral  pipes  running  from  it.  During  1898  there 
was  placed  on  the  force  main  over  the  check  valve  at  the  pump- 
ing station,  an  air  chamber  10  inches  in  diameter  and  10  feet  high 
to  assist  in  cushioning  water  rams  on  the  mains  due  to  the  sudden 
opening  and  closing  of  cocks  and  valves  on  domestic  service  pipes. 
Owing,  however,  to  the  lack  of  convenient  facilities  for  charging 
the  chamber  with  air,  this  was  only  partially  successful.  "To 
overcome  the  defect,"  a  report  of  the  Trustees  reads,  "we  have 
placed  a  glass  gauge  on  the  air  chamber  and  a  small  crank  and  fly- 
wheel air  pump  in  the  engine  room,  by  means  of  which  the  air 
chamber  may  be  conveniently  charged  to  a  fixed  level  and  a  good 
air  cushion  be  always  provided  to  receive  the  shocks  on  the  pipe 
system.  The  beneficial  effect  of  this  is  shown  by  the  charts  taken 
from  the  recording  gauge  at  the  pumping  station.  Heretofore, 
the  rams  on  the  pipe  system  would  range  from  20  to  40  pounds 
on  the  gauge  and  four  or  five  might  be  noticed  in  an  hour,  while 
with  the  charged  air  vessel  the  rams  are  confined  within  10  pounds 
and  the  air  cushion  is  now  so  sensitive  as  to  respond  to  all  minor 
fluctuations  of  pressure  on  the  pipe  system." 


250  WATER-WORKS    MANUAL. 

Accumulators  and  air  chambers  do  not  afford  storage  and  are 
poor  substitutes  for  standpipes  in  consequence.  This  objection 
does  not  hold  true  of  the  system  of  compressed  air  and  water  tanks 
in  use  at  Southampton  and  Babylon,  N.  Y.,  and  several  other 
places,  which  may  be  used  whenever  a  standpipe  is  undesirable. 
The  system  was  the  joint  invention  of  the  late  William  E.  Worth- 
en  and  Mr.  Oscar  Darling  and  has  a  number  of  strong  points,  par- 
ticularly where  the  water  supply  is  drawn  from"  wells  and  must 
not  be  exposed  to  the  light  before  delivery  to  consumers. 

In  its  main  features  the  system  involves  the  use  of  closed 
steel  water  tanks  of  any  desired  capacity  into  which  the  supply 
is  pumped,  closed  steel  air  tanks  into  which  compressed  air  is 
forced  by  a  compressor  in  the  pumping  station,  and  a  system  of 
pipes  and  valves  connecting  the  two  sets  of  tanks.  At  Babylon, 
there  are  four  water  tanks  with  a  combined  capacity  of  100,000 
gallons,  and  two  air  tanks  constructed  to  carry  a  maximum  pres- 
sure of  150  pounds.  Under  ordinary  conditions  the  reducing 
valve  on  the  pipe  between  the  air  and  water  tanks  keeps  the  pres- 
sure on  the  latter  at  40  pounds,  but  in  case  of  fire  the  full  pressure 
of  the  air  is  thrown  on  the  water  tank  and  the  supply  is  delivered 
under  good  fire  pressure.  All  the  tanks  are  underground  in  an 
extension  of  the  pumping  station,  and  the  operating  valves  can 
be  reached  at  once  by  the  engineer.  The  system  presents  ad- 
vantages well  worth  study,  but  these  and  the  details  of  operation 
are  so  well  stated  in  the  trade  literature  of  the  people  controlling 
the  system  that  it  is  unnecessary  to  go  into  further  explanation' 
here. 


CHAPTER  XIX.— THE  QUANTITY  OF  WATEE  TO  BE 

PROVIDED. 

There  are  probably  more  mistakes  made  in  the  estimates  for  the 
volume  of  water  needed  by  towns  and  small  cities  than  in  any 
other  feature  of  water-works  design.  The  assumption  is  fre- 
quently made  that  a  liberal  allowance,  say  60  gallons,  for  the  daily 
supply  of  each  person  in  the  community  and  a  liberal  allowance 
for  the  rate  of  increase  in  the  population,  are  all  the  factors  to  be 
considered.  Now  a  good  fire  stream  takes  water  at  the  same  rate 
as  about  6,000  people  using  the  water  for  domestic  purposes  alone, 
so  a  bad  fire  in  a  town  of  10,000  people  could  be  checked  with 
difficulty  if  the  water-works  were  designed  on  this  erroneous  basis. 
It  is  evident,  therefore,  that  fire  protection  should  play  a  very  im- 
portant part  in  the  final  selection  of  plans  for  works. 

The  amount  of  water  used  for  all  purposes  outside  of  fire  pro- 
tection varies  somewhat  according  to  the  character  of  the  popula- 
tion. In  a  town  with  many  detatched  houses  surrounded  by  lawns 
which  need  sprinkling  in  summer,  50  to  60  gallons  per  capita  daily 
should  be  provided  for  a  population  of  20,000.  In  a  mill  village 
of  10,000  population  where  but  one  or  two  fixtures  will  be  used 
in  a  house,  40  gallons  per  capita  may  be  more  than  enough.  The 
amount  needed  for  manufacturing  purposes  must  be  learned  from 
a  study  of  existing  establishments,  as  industries  like  breweries  or 
dyeworks  require  much  larger  supplies  than  machine  shops  or 
weaving  mills.  If  there  is  plenty  of  water  available  it  is  well  to 
see  if  any  of  the  railways  in  the  vicinity  will  buy  water,  for  a 
considerable  revenue  may  be  obtained  from  supplies  for  locomo- 
tives if  the  price  asked  is  a  reasonable  one.  It  is  very  important 
to  provide  for  a  large  consumption,  for  there  is  sure  to  be  some 
waste  and  a  failure  of  a  water  supply,  even  if  it  is  but  partial,  is 
a  serious  matter.  In  addition  to  the  discomfort  caused  the  peo- 
ple, and  the  unsanitary  conditions  which  result,  such  a  failure  is 


252  WATER-WORKS    MANUAL. 

noticed  on  the  fire  insurance  companies'  records  and  tends  to  pre- 
vent the  industrial  development  of  the  place. 

It  has  been  learned  by  experience  that  the  draft  during  a  few 
hours  may  be  at  twice  the  average  daily  rate  per  capita  during  the 
year.  On  Monday  mornings,  for  instance,  when  washing  is  done, 
and  late  in  the  afternoons  of  hot  days  when  lawns  are  sprinkled, 
there  is  an  excessive  demand  for  water,  for  which  provision  should 
be  made. 

FIRE  PROTECTION. 

In  studying  the  fire  protection  which  a  water  plant  should  af- 
ford a  town,  attention  must  be  paid  to  the  rules  laid  down  by  Mr. 
John  K.  Freeman,  M.  Am.  Soc.  C.  E.,  in  a  valuable  paper  before 
the  New  England  Water- Works  Association.  Pipes  intended  to 
supply  water  for  domestic  purposes  only  might  start  with  main 
arteries  and  taper  down  to  small  veins  at  the  border  of  the  district. 
Fire  protection,  on  the  other  hand,  often  demands  a  concentration 
of  all  the  water  the  works  can  furnish  at  one  point,  which  may 
happen  to  be  almost  anywhere.  Moreover,  there  may  be  two  fires 
to  put  out  at  the  same  time,  and  the  works  should  be  designed  for 
such  a  contingency,  although  it  would  be  unreasonable  to  design 
them  for  two  great  simultaneous  conflagrations. 

A  stream  from  a  hose  does  not  put  out  a  fire  by  wetting  the 
flames.  A  fire  involves,  first,  the  roasting  of  the  material  so  as 
to  give  off  gases,  and,  second,  the  burning  of  these  gases.  The 
stream  of  water  is  intended  to  chill  the  burning  materials  so  that 
no  combustible  gases  are  given  off.  If  the  fire  is  a  strong  one  and 
the  stream  of  water  small,  most  of  the  water  will  be  evaporated  as 
it  passes  through  the  flames  and  but  little  reach  the  place  where 
it  is  of  any  use.  Hence,  good  substantial  streams  are  needed,  and 
feeble  squirts  from  a  small  hose  are  of  no  value  except  in  checking 
a  fire  as  it  begins.  Large  fire  streams  are  of  course  out  of  the 
question  in  small  cities,  but  it  is  well  to  remember  that  six  streams 
from  a  1-inch  nozzle,  each  delivering  200  gallons  a  minute,  are 
worth  more  in  putting  out  a  fire  than  ten  f-inch  streams  of  120 
gallons  each.  Both  theory  and  practice  have  settled  on  the  1J- 
inch  smooth  nozzle  as  the  best  general  size  for  use,  but  it  is  prob- 
ably too  large  for  the  class  of  works  described  in  this  book,  ex- 
cept where  large  valuable  buildings  must  be  protected.  A  1-inch 
stream  will  answer  well  for  most  purposes  in  a  residence  or  subur- 
ban town  and  a  f-inch  stream  will  be  sufficient  for  many  places. 


WATER-WORKS    MANUAL.  253 

The  afflictions  that  follow  fires  are  too  serious  to  be  trifled  with  by 
adopting  little  streams.  Mr.  Freeman  points  out  that  a  burning 
business  block  50  feet  square  and  three  stories  high  demands  just 
as  many  fire  streams  to  extinguish  it  and  to  protect  the  buildings 
each  side  of  it  when  it  stands  in  a  village  of  2,500  inhabitants  as 
when  it  stands  in  a  city  of  twenty  times  that  population. 

The  amount  of  water  in  a  fire  stream  depends  upon  the  size  of 
the  nozzle  and  the  pressure  of  the  water  at  its  base.  So  far  as  the 
size  of  the  nozzle  is  concerned,  it  is  well  to  provide  250  gallons  per 
minute  for  each  l|-inch  nozzle,  200  gallons  for  each  one  of  1  inch, 
.and  120  gallons  for  each  one  of  f-inch  bore.  These  quantities  are 
based  on  a  pressure  of  about  45  pounds  at  the  base  of  the  nozzle. 

Whether  such  a  pressure  can  be  obtained  depends  upon  whether 
good  judgment  has  been  displayed  in  building  the  works.  Mr. 
Freeman's  words  are  quoted  verbatim,  as  they  express  the  opinion 
of  the  leading  authority  on  this  subject  in  the  United  States. 

"A  IJ-inch,  250-gallon  stream  calls  for  a  velocity  of  16.34  feet 
per  second  in  the  hose.  This  velocity  is  far  beyond  what  in  other 
arts  is  regarded  as  the  economical  limit  for  the  velocity  of  flowing 
water.  In  city  water  mains  from  2  to  3  feet  is  the  common  ve- 
locity; in  sewers  the  same  is  true;  in  the  flumes  supplying  turbine 
water-wheels  3  to  5  feet  can  seldom  be  exceeded  with  propriety, 
and  in  the  short  delivery  pipes  to  low-lift  centrifugal  drainage 
pumps,  10  feet  per  second  is  the  common  maximum. 

"In  fire  hose  we  are  held  up  to  high,  force-wasting  velocities  by 
the  all  important  necessity  of  keeping  the  hose  so  small  in  diameter 
and  weight  that  men  can  grasp  it  firmly,  handle  it  easily,  and  move 
it  around  quickly.  Practical  experience  has  settled  on  2^  inches 
internal  diameter  as  the  favorite  size. 

"To  deliver  250  gallons  per  minute  with  only  3  feet  per  second 
velocity  would  require  a  hose  or  pipe  nearly  6  inches  in  diameter. 
In  other  words  you  force  as  large  a  volume  of  water  through  a  2^- 
inch  hose  as  would  go  through  a  6-inch  pipe  at  the  3-foot  velocity 
common  in  water  mains. 

"It  is  true  economy  to  be  generous  in  the  number  of  hydrants 
and  thus  save  money  on  the  outlay  for  hose  and  for  making  good 
its  annual  depreciation.  Moreover,  by  the  use  of  short  lines  of 
hose,  there  is  a  great  gain  in  the  efficiency  of  a  stream  by  its.  in- 
creased force  and  greater  volume  and  the  greater  height  and  dis- 
tance to  which  it  will  reach. 


254  WATER-WORKS    MANUAL. 

"Good  jacketed  fire  hose  now  costs  about  75  cents  per  foot.  A 
6-inch  tar-coated  heavy  cast-iron  main  can  be  laid  for  about  75 
cents  per  foot,  cost  of  pipe,  trench,  lead  and  laying  all  included. 
A  city  can  buy  a  good  two-way  hydrant  for  less  than  the  price  of 
50  feet  of  good  fire  department  hose  and  its  water  department  can 
buy  and  put  down  100  feet  of  the  best  6-inch  cast-iron  water  pipe 
for  just  about  the  same  price  that  its  fire  department  pays  for  an 
equal  length  of  hose.  The  life  of  the  hose  will  not  average  more 
than  5  to  10  years.  The  pipes  may  last  50  years. 

"The  bed-rock  facts  on  which  our  rule  for  spacing  hydrants 
must  rest  are  that  a  good  stiff  1^-inch  standard  stream  of  250  gal- 
lons per  minute  cannot  be  pushed  through  more  than  400  feet  of 
even -the  very  best  and  smoothest  hose  by  a  hydrant  pressure  of  100 
pounds. 

"The  water-works  giving  a  hydrant  pressure  of  more  than  100 
pounds  are  comparatively  few  and  the  liability  of  accident  is  so  in- 
creased that  it  is  as  a  general  rule  advisable  not  to  exceed  100 
pounds  hydrant  pressure.  The  average  New  England  pressure  is 
only  about  75  pounds,  therefore  if  one  would  use  hose  lines  more 
than  300  feet  long  he  must  sacrifice  the  power  or  size  and  the  effi- 
ciency of  the  jet,  or  use  a  steam  fire  engine  to  give  it  an  extra  push. 

"This  limit  to  the  length  of  hose  through  which  a  good  stream 
can  be  forced  indicates  that  as  a  rule  there  should  be  hydrants 
enough  around  or  near  to  any  very  important  block  of  buildings 
in  a  city  of  moderate  size  without  steamers  and  with  80  to  100 
pounds  hydrant  pressure,  so  that  eight  hose  streams  could  be  led 
to  it  without  the  average  line  of  hose  being  more  than  300  to  400 
feet  in  length,  and  with  no  one  of  these  eight  lines  more  than 
500  feet  in  length.  If  the  hydrant  pressure  is  but  60  to  70  pounds, 
then  the  hydrants  should  be  so  placed  with  reference  to  any  im- 
portant building  that  half  the  whole  number  of  streams  could  be 
drawn  through  lines  of  hose  not  exceeding  250  feet  in  length." 

The  application  of  these  general  principles  to  the  local  condi- 
tions of  any  particular  town  calls  for  careful  study.  Where  the 
buildings  are  surrounded  by  lawns  and  a  fire  in  one  does  not  en- 
danger others  two  streams  are  enough.  As  175-gallon  streams 
under  30  pounds  nozzle  pressure  give  fair  protection  for  ordinary 
detached  dwellings,  a  500-foot  line  of  2|-inch  hose  may  be  toler- 
ated if  the  hydrant  pressure  is  75  pounds  or  more.  Four  hundred 
feet  is  a  much  safer  allowance,  however,  for  the  hydrant  spacing 


WATER-WORKS    MANUAL.  255 

ID  such  districts,  and  in  the  business  portion  of  the  town  about  250 
feet  is  the  proper  spacing. 

There  is  little  advantage  in  using  four-way  hydrants  in  the  class 
of  works  under  consideration.  The  two-way  hydrants  largely 
avoid  the  danger  of  a  total  lack  of  water  from  freezing,  which  is 
an  important  matter  to  consider.  The  position  of  the  hydrants 
should  be  determined  while  on  the  ground  and  every  detail  of  the 
surroundings  can  be  taken  in  at  a  glance.  If  they  are  located 
from  a  map  the  result  may  be  as  surprising  as  in  a  plant  once  ex- 
amined by  the  writer,  which  had  a  couple  of  hydrants  at  a  place 
where  the  only  structures  within  a  radius  of  500  feet  were  the 
tombstones  of  a  large  cemetery  and  a  small  open  shed  of  rough 
boards  used  by  a  stone  cutter. 

Various  tables  have  been  prepared  to  show  the  number  of 
streams  which  should  be  available,  simultaneously  in  towns  of 
different  populations.  As  a  basis  of  discussion  among  specialists 
they  are  of  value,  but  they  are  liable  to  mislead  people  who  have 
not  given  serious  study  to  the  subject.  Their  lack  of  general  ap- 
plicability may  be  readily  understood  by  considering  two  typical 
villages  of  5,000  people  each.  One  is  a  town  which  contains  few 
places  of  business  and  no  factories;  a  suburban  residence  town,  in 
fact.  The  other  is  a  mill  village,  where  the  welfare  of  the  entire 
community  depends  on  a  couple  of  factories.  In  the  first  case, 
from  four  to  six  streams  are  needed;  but  in  the  latter,  ten  or  more 
strong  250-gallon  streams  may  be  demanded  to  protect  the  indus- 
tries which  are  the  sole  support  of  the  entire  community.  Ample 
allowance  in  this  matter  is  all  the  more  important  because  of  the 
waste  of  water  in  case  the  service  pipe  of  a  burning  building  breaks. 
There  have  been  cases,  according  to  Mr.  Freeman,  where  a  small 
public  water  supply  has  been  rendered  utterly  useless  by  the  break- 
ing, during  the  early  stages  of  a  fire,  of  a  3-inch  or  a  4-inch  pipe 
entering  a  building. 

In  all  water-works  depending  on  an  elevated  tank  or  reservoir 
for  water  during  the  night  or  while  reserve  pumps  are  being 
brought  into  service,  attention  must  be  paid  to  the  needs  of  fire 
protection  in  determining  its  size.  The  minimum  supply  which 
the  Factory  Mutual  Insurance  Companies  request  for  the  protec- 
tion of  large  isolated  mills  is  one  hour's  draft  of  the  full  number  of 
fire  streams.  This  may  be  taken  as  a  satisfactory  basis  of  figuring 
for  small  water-works  on  the  direct-pumping  system,  where  the 


256  WATER-WORKS    MANUAL. 

pumps  can  be  started  quickly,  day  or  night.  If,  on  the  other 
hand,  the  reservoir  is  supplied  by  gravity  or  through  a  long  force 
main,  economy  will  probably  result  in  most  cases  if  the  gravity 
conduit  or  the  pumping  station  with  its  force  main  is  proportioned 
for  the  maximum  domestic  draft,  and  the  excess  water  is  stored  in 
a  large  reservoir  holding  at  the  very  least  six  hours'  supply  for  the 
maximum  number  of  fire  streams.  As  the  maximum  draft  is  about 
twice  the  average  amount  except  in  mill  villages  and  other  special 
cases,  there  will  be  little  difficulty  in  obtaining  the  requisite  vol- 
ume of  water  for  storage. 

SIZE    OF    STREET    MAINS. 

The  sizes  of  pipe  to  be  laid  in  any  street  should  be  determined 
from  the  needs  of  fire  protection  in  the  first  place,  for  if  this  is 
done  it  will  generally  be  found  that  they  are  ample  for  delivering 
the  domestic  supply.  The  fundamental  fact  to  be  borne  in  mind 
is  that  small  pipes  cause  a  great  loss  in  water  pressure  and  a  decrease 
in  the  efficiency  of  fire  streams.  The  good  influence  of  a  large 
supply  pipe,  ample  pumping  capacity  and  abundant  storage  in  an 
elevated  reservoir  or  tank  may  be  largely  counteracted  by  small 
or  badly  arranged  street  mains  and  an  insufficient  number  of  badly 
located  hydrants.  The  loss  of  pressure  due  to  friction  in  clean, 
straight  pipes  1,000  feet  long,  but  of  different  diameters,  when 
discharging  150  gallons  per  minute,  is  as  follows: 

Diameter  of  pipe,  inches 4  6  8  10  )2 

Friction  loss,  feet 1703         2.09          0.48  O.l5          0.06 

These  figures  give  the  most  favorable  results.  After  the  pipes 
have  been  in  use  a  number  of  years  and  their  inner  surfaces  are 
roughened  by  tubercles  which  diminish  their  bore  and  increase 
their  frictional  resistance  to  the  flow  of  water,  it  may  easily  happen 
that  the  resistances  will  be  doubled,  particularly  when  it  is  consid- 
ered that  there  are  bends  and  elbows  in  a  line  of  street  main.  Un- 
der such  practical  conditions,  a  4-inch  pipe  1,000  feet  long  will  re- 
quire a  head  of  34  feet  to  deliver  150  gallons  per  minute,  while  a 
6-inch  pipe  will  need  a  head  of  less  than  4 J  feet.  It  is  very  evident 
therefore  that  no  reliance  can  be  placed  on  4-inch  pipe  for  fire  pro- 
tection unless  it  is  used  in  short  lengths  fed  from  both  ends  by 
larger  pipes.  It  is  useless  to  expect  that  a  half  mile  of  4-inch  pipe, 
tapped  every  hundred  feet  or  so  by  domestic  service  pipes,  will  fur- 
nish at  its  end  a  stream  large  enough  for  any  other  use  than 
washing  carriages  or  windows. 


WATER-WORKS    MANUAL.  257 

On  the  other  hand  it  is  very  easy  to  select  street  mains  of  too^ 
large  size.  No  one  who  has  not  worked  out  a  number  of  actual 
problems  in  street-main  hydraulics  can  appreciate  what  differences 
in  the  cost  of  the  system  can  be  produced  by  variations  in  the  ar- 
rangement of  piping  to  obtain  the  same  pressures.  It  will  prob- 
ably be  found  best,  in  attacking  such  problems,  to  prepare  a: 
rough  sketch  of  the  streets  of  the  town,  on  which  the  hydrants  and 
the  relative  elevations  are  indicated.  The  tables  of  fire  streams 
accompanying  this  chapter  will  furnish  data  for  determining  the 
pressure  at  the  hydrants  when  discharging  streams  of  the  desired 
character.  The  elevation  of  the  hydrant  above  a  given  plane 
must  carefully  be  considered,  because  it  is  much  easier  to  furnish 
75-pound  pressure  at  the  foot  of  a  hill  than  at  the  top.  Fortunate- 
ly the  greatest  need  of  fire  protection  rarely  occurs  at  the  summit 
of  hills.  It  seems  hardly  necessary  to  mention  this  point,  yet  most 
engineers  have  doubtless  seen  hydrants  which  furnish  little  more 
than  a  dribble  because  they  are  placed  at  elevations  exceeding  the 
available  pressure  on  the  distribution  mains. 

Having  located  the  hydrants,  a  heavy  fire  should  be  assumed  at 
some  place.  The  hydrants  within  reach  will  throw  two  or  more 
streams  each.  The  street  mains  must  now  be  proportioned  so  as 
to  furnish  the  desired  quantity  of  water  under  the  necessary  pres- 
sure and  also  the  maximum  quantity  required  for  domestic  service. 
A  repetition  of  this  process  of  computation  in  other  parts  of  a 
town,  care  being  taken  every  time  to  allow  for  the  elevation  of 
the  hydrant  as  well  as  the  pressure  needed  for  the  streams,  will 
furnish  an  indication  of  the  nature  of  the  piping  which  is  required. 
The  remaining  portions  can  be  readily  interpolated  and  it  then 
becomes  necessary  to  arrange  for  the  connection  of  the  street 
mains  with  the  supply  main.  This  is  a  question  which  must  be 
solved  independently  for  each  town.  The  most  unfavorable  situa- 
tion arises  where  a  line  of  important  buildings  extends  along  a 
single  street;  the  easiest  problem  to  solve  is  where  the  buildings 
are  fairly  uniformly  distributed  on  a  network  of  streets,  which  can 
be  threaded  by  lines  of  small  pipe,  possibly  4  inches  in  some  places, 
which  are  fed  by  larger  mains  surrounding  or  intersecting  them,  as 
the  case  may  be. 

In  communities  of  but  a  few  thousand,  these  recommendations 
must  be  modified  by  the  all-powerful  restrictions  of  limited  finan- 
cial resources.  It  is  in  these  small  plants  that  the  engineer  has 


258 


WATER-WORKS    MANUAL. 


an  opportunity  to  exercise  his  common-sense  and  technical  ability 
to  the  utmost.  Every  $100  additional  cost  must  be  carefully  con- 
sidered. In  some  places,  such  as  the  summits  of  hills  or  clusters  of 
houses  apart  from  the  body  of  the  town,  it  may  prove  best  to  rec- 
ommend insurance  rather  than  hose  streams  as  a  protection  against 
fire  losses.  In  any  community  it  is  the  service  of  the  whole  and 
not  the  benefit  of  the  individual  which  should  be  considered.  If 
the  financial  resources  of  the  town  do  not  permit  the  construction 
of  works  which  are  of  equal  service  to  all,  this  is  no  reason  for 
voting  down  such  a  desirable  public  improvement  as  a  water  plant 
for  domestic  service  and  fire  protection  for  most  of  the  homes. 

FIRE      STREAMS. 

On  account  of  the  great  importance  of  a  thorough  study  of  fire 
protection  in  designing  water-works,  a  subject  which  usually  re- 

FIRE-STREAM  DATA  FOR  %-INCH  SMOOTH  NOZZLE. 
(This  table  also  serves  for  a  %-inch  ring  nozzle.) 


1 

8" 

Best  fire 

1 

Hydrant  pressure  in  pounds  required  to  maintain  pressure 
at  base  of  stay  pipe  as  per  column  1,  through  2^-inch 
hose  lines  mentioned. 

g 

jet. 

G 

OQ 

£ 

P. 

•d 

OQ 

50ft. 

100  ft. 

200  ft. 

300  ft. 

400ft. 

500  ft. 

o 

1 

H 

*: 

O 
O 

d 

i 

§ 

1 

d 

1 

g 

1 

g 

g 

a 

o> 

I* 

0) 

— 

*d 

jd 

pj3 

O 

2 

.n 

a 

G) 

QD 

& 

a 

2 

a 

- 

M 

1 

i 

H 

S. 

i 

P 

I 

C3 

3 

tf 

•1 

5 

37 

5 

5 

6 

5 

6 

6 

7 

6 

8 

6 

9 

7 

10 

17  ' 

19 

52 

11 

10 

12 

11 

13 

11 

14 

12 

16 

13 

17 

13 

15 

25 

24 

64 

16 

16 

17 

16 

19 

17 

22 

18 

24 

19 

26 

20 

20 

33 

29 

73 

22 

21 

23 

22 

26 

23 

29 

24 

32 

25 

34 

26 

25 

41 

33 

82 

27 

26 

29 

27 

32 

28 

36 

30 

39 

31 

43 

33 

30 

48 

37 

90 

33 

31 

35 

32 

39 

34 

43 

36 

47 

38 

52 

40 

35 

55 

41 

97 

38 

37 

40 

38 

45 

40 

50 

42 

55 

44 

60 

46 

40 

60 

44 

104 

43 

42 

46 

43 

52 

46 

58 

48 

63 

50 

69 

53 

45 

64 

47 

110 

49 

47 

52 

48 

.  58 

51 

65 

54 

71 

57 

77 

59 

50 

67 

50 

116 

54 

52 

58 

54 

65 

57 

72 

60 

79 

63 

86 

66 

55 

70 

52 

122 

60 

58 

64 

59 

71 

63 

79 

66 

87 

69 

95 

73 

60 

72 

54 

127 

65 

63 

69 

65 

78 

68 

86 

72 

95 

76 

103 

79 

65 

74 

56 

132 

71 

68 

75 

70 

84 

74 

93 

78 

103 

82 

112 

86 

70 

76 

58 

137 

76 

73 

81 

75 

91 

80 

101 

84 

110 

88 

120 

92 

75 

78 

60 

142 

81 

79 

87 

81 

97 

85 

103 

90 

118 

94 

129 

99 

80 

79 

62 

147 

87 

84 

93 

86 

104 

91 

115 

96 

126 

101 

138 

106 

85 

80 

61 

151 

92 

89 

98 

92 

110 

97 

122 

102 

134 

107 

146 

112 

90 

81 

65 

156 

98 

94 

104 

97 

117 

102 

129 

103 

142 

113 

155 

119 

95 

82 

66 

160 

103 

99 

110 

102 

123 

108 

137 

114 

150 

120 

163 

125 

100 

83 

68 

164 

109 

105 

116 

108 

130 

114 

144 

120 

158 

126 

172 

132 

Eighty  pounds  per  square  inch  is  now  considered  the  best  hydrant  pressure  for 
general  use  ;  100  pounds  should  not  be  exceeded  except  for  very  high  buildings.  If 
the  nozzle  is  much  higher  or  lower  than  the  hydrant,  allowance  for  difference  of 
level  must  be  made  on  hydrant  pressure;  lo  feet  in  height  corresponds  to  4J^  pounds 
water  pressure. 

The  above  pressures  are  at  the  hydrant  head  while  stream  is  flowing.  The  cor- 
responding pump  or  reservoir  pressure  must  be  greater  than  the  hydrant  pressure 
by  an  amount  equal  to  the  friction  loss  between  the  hydrant  head  and  pump  or 
reservoir. 


WATER-WORKS    MANUAL. 


259 


ceives  inadequate  emphasis  in  books  on  water-works  construction, 
a  number  of  tables  are  presented  in  pages  258  to  262  giving  the 
results  of  experiments  with  fire  streams  made  by  Mr.  Freeman  and 
described  by  him  in  a  paper  of  unusual  value  in  the  "Transactions" 
of  the  American  Society  of  Civil  Engineers  for  November,  1889. 
A  study  of  these  tables  will  give  a  better  idea  of  the  relations  of  the 
various  conditions  influencing  fire  streams  than  the  reading  of 
many  pages  of  generalities  on  the  subject. 

It  will  be  noticed  that  these  tables  are  all  for  smooth  conical 
nozzles.  The  reason  for  this  is  that  the  experiments  demonstrate 
beyond  question  that  this  type  is  more  effective  than  ring  nozzles. 
The  latter  throw  less  water  than  a  smooth  nozzle  of  the  same  diam- 
eter, with  the  same  hydrant  pressure  and  hose;  consequently  the 


FIRE-STREAM  DATA  FOR  %-!NCH  SMOOTH  NOZZLE. 
(This  table  also  serves  for  a  1-inch  Ring  Nozzle. » 


1 

Best  fire 

a 

Hydrant  pressure  in  pounds  required  to  maintain  pressure 
at  the  base  of  play  pipe  as  per  column  1,  through 
2!^-inch  hose  lines  mentioned. 

f-i 

jet. 

c 

1 

1 

50ft. 

100ft. 

200ft. 

300ft. 

400ft. 

500ft. 

P. 

P, 

1 

+3 

d 

en 

q 

d 

Si 

d 

. 

^ 

jg 

h 

c 

(J 

gj 

pi 
o 

J 

-*-^ 

ff 

£2 

& 

2 

- 

® 

^ 

,8 

a) 

pO 

,0 

*? 

o 

s 

a 

a 

f> 

fl 

pQ 

p 

a 

fi 

a 

C 
HH 

8 

1 

o 

5 

- 

i-" 

3 

2 

3 

1 

3 

(§ 

2 

1 

5 

50 

6 

5 

6 

6 

8 

6 

9 

7 

10 

7 

12 

8 

10 

18 

"21" 

71 

12 

11 

13 

11 

16 

13 

18 

14 

21 

15 

23 

16 

15 

26 

27 

87 

17 

16 

19 

17 

23 

19 

27 

21 

31 

22 

35 

24 

20 

34 

33 

100 

23 

22 

26 

23 

31 

25 

36 

27 

42 

30 

47 

32 

25 

42 

38 

112 

29 

27 

32 

29 

39 

31 

45 

34 

37 

59 

40 

30 

49 

42 

123 

35 

33 

39 

34 

47 

38 

54 

41 

62 

45 

70 

48 

35 

46 

133 

41 

38 

45 

40 

54 

44 

64 

48 

73 

52 

82 

56 

40 

62 

49 

142 

46 

43 

52 

46 

62 

50 

73 

55 

83 

59 

94 

64 

45 

67 

52 

150 

5' 

49 

58 

51 

70 

57 

82 

62 

94 

67 

105 

72 

50 

71 

55 

159 

58 

54 

65 

57 

78 

63 

91 

69 

104 

74 

117 

80 

55 

74 

58 

166 

64 

60 

71 

63 

85 

69 

100 

75 

114 

82 

129 

88 

60 

77 

61 

174 

70 

65 

78 

69 

93 

75 

109 

82 

125 

89 

140 

96 

65 

79 

64 

181 

75 

71 

84 

74 

101 

82 

118 

89 

135 

96 

152 

104 

70 

81 

66 

188 

81 

76 

90 

80 

109 

88 

127 

98 

145 

104 

164 

112 

75 

83 

68 

194 

87 

82 

97 

86 

117 

94 

136 

103 

156 

111 

175 

120 

80 

85 

70 

201 

93 

87 

103 

91 

124 

101 

145 

110 

166 

119 

187 

128 

85 

87 

72 

207 

99 

92 

110 

97 

1H2 

107 

154 

116 

177 

126 

199 

136 

90 

88 

74 

213 

104 

98 

116 

103 

140 

113 

163 

123 

187 

134 

211 

144 

95 

89 

75 

219 

110 

103 

123 

109 

148 

119 

173 

130 

197 

141 

222 

152 

luo 

90 

76 

224 

116 

109 

129 

114 

155 

126 

182 

137 

208 

148 

234 

160 

Eighty  pounds  per  square  inch  is  now  considered  the  best  hydrant  pressure  for 
general  use;  lOu  pounds  should  not  be  exceeded  except  for  very  high  buildings.  If 
the  nozzle  is  much  higher  or  lower  than  the  hjdrant,  allowance  for  difference  of 
level  must  be  made  on  hydrant  pressure;  10  feet  in  height  corresponds  to  4U pounds 
water  pressure. 

Th"  abov*' pressures  are  at  the  hydrant  head  while  stream  is  flowing.  The  cor- 
responding pump  or  reservoir  pres-ure  must  be  greater  than  the  hydrant  pressure 
by  an  amount  equal  to  the  friction  loss  between  the  hydrant  head  and  pump  or 
reservoir 


260 


WATER-WORKS    MANUAL. 


friction  loss  in  the  hose  is  less  and  the  stream  is  carried  somewhat 
higher  and  farther,  though  of  much  smaller  volume. 

All  the  figures  in  the  table  are  for  2^-inch  hose,  which  is  now 
the  standard  size.  A  slight  variation  in  the  diameter  makes  an 
important  change  in  the  friction  loss.  Using  the  same  quality  and 
length  of  hose  to  discharge  a  definite  quantity  of  water,  and  desig- 
nating the  friction  loss  in  a  2-J-inch  hose  as  100,  the  loss  in  lines  of 
different  diameters  will  be  about  as  follows: 


Diameter 
Loss  . .   . 


2/g 
129 


100  129  170  200          3<J5 

In  other  words,  it  will  require  three  times  the  head  at  the  hy- 
drant to  produce  the  same  stream  with  a  2-inch  hose  as  with  one 
half  an  inch  larger  in  diameter.  It  seems  hardly  necessary  to  say 
anything  further  in  favor  of  the  large  hose. 

FIRE-STREAM  DATA  FOR  I-INCH  SMOOTH  NOZZLE. 


1 

» 

Hydrant  pressure  in  pounds  required  to  maintain  pressure 
at  base  of  play  pipe  as  per  column  1,  through  2^-inch 

rf 

Best  fire 

"S 

hose  lines  mentioned. 

(4 

jet. 

a 

03 

a 

£ 

50ft. 

100ft. 

200ft. 

300ft. 

400ft. 

500ft. 

P. 

p< 

j 

+3 

£ 

M 

c 

h 

£ 

a 

1 

i 

0> 

s 

1 

g 

1 

d 

1 

•53 

03 

1 

.g 

,Q 
£ 

a 

JD 

a 

1 

I 

C 

•3 

ja 

a 

»—  i 

o 
W 

0> 

M 

^ 

- 

3 

tf 

^ 

tf 

*-' 

C4 

3 

« 

* 

5 

66 

6 

6 

8 

6 

10 

7 

12 

8 

14 

9 

17 

10 

10 

18 

"2!" 

93 

13 

12 

15 

12 

20 

14 

24 

16 

29 

18 

33 

20 

15 

26 

30 

114 

19 

17 

23 

19 

29 

22 

36 

2-5 

43 

2H 

50 

30 

20 

35 

37 

132 

26 

23 

30 

25 

39 

29 

48 

33 

57 

37 

66 

41 

25 

43 

42 

147 

32 

29 

38 

31 

49 

36 

60 

41 

71 

46 

83 

51 

30 

51 

47 

161 

38 

34 

45 

37 

59 

43 

72 

49 

86 

55 

99 

61 

35 

58 

51 

174 

45 

40 

53 

44 

68 

51 

84 

57 

100 

64 

116 

71 

40 

64 

55 

186 

51 

46 

60 

50 

78 

58 

96 

66 

114 

73 

132 

81 

45 

69 

58 

198 

57 

52 

68 

56 

88 

65 

108 

74 

129 

83 

149 

91 

50 

73 

61 

208 

64 

57 

75 

62 

98 

72 

120 

82 

143 

92 

166 

102 

55 

76 

64 

218 

70 

63 

83 

69 

108 

79 

132 

90 

157 

101 

182 

112 

60 

79 

67 

228 

77 

69 

90 

75 

117 

87 

144 

98 

171 

110 

199 

122 

65 

82 

70 

237 

83 

75 

98 

81 

127 

94 

156 

107 

186 

119 

215 

132 

70 

85 

72 

246 

89 

80 

105 

87 

137 

101 

168 

115 

201) 

128 

232 

142 

75 

87 

74 

255 

96 

86 

113 

94 

147 

108 

181 

123 

214 

138 

248 

152 

80 

89 

76 

263 

102 

92 

120 

100 

156 

115 

193 

131 

229 

147 

162 

85 

91 

78 

274 

109 

98 

128 

106 

166 

123 

205 

139 

243 

156 

173 

90 

92 

80 

279 

115 

103 

135 

112 

176 

130 

217 

147 

257 

165 

'| 

183 

95 

94 

82 

287 

121 

109 

143 

118 

186 

137 

229 

156 

174 

193 

100 

93 

83 

295 

128 

115 

150 

125 

195 

144 

241 

164 

.... 

183 

2)3 

Eighty  pounds  per  square  inch  is  now  considered  the  best  hydrant  pressure  for 
general  use;  1»0  pounds  should  not  be  exceeded  except  for  very  high  buildings.  If 
the  nozzle  is  much  hiorher  or  lower  than  the  hydrant,  allowance  for  difference  of  level 
must  be  made  on  hydrant  pressure;  10 feet  in  beight  corresponds  to 4J^ pounds  water 
pressure. 

The  above  pressures  are  at  the  hydrant  head  while  stream  is  flowing.  The  cor- 
responding pump  or  reservoir  pressure  must  be  greater  than  the  hydrant  pressure 
by  an  amou-t  equal  to  the  friction  loss  between  the  hydrant  head  and  pump  or 
reservoir. 


WATER-WORKS    MANUAL. 


261 


The  two  classes  of  hose  mentioned  in  the  tables  are  unlined 
linen  and  the  ordinary  best-quality  rubber-lined,  grade  with  a 
smooth  interior.  What  is  known  as  mill  hose  gives  results  between 
these  two;  it  is  a  rubber-lined  cotton  hose  with  a  rough  interior. 
The  couplings  and  other  fittings  which  have  threads  should  be 
made  to  the  gauge  of  some  large  city  in  the  vicinity.  Over  200 
gauges  are  used  in  the  country;  a  ridiculous  condition  which  should 
be  remedied  by  the  adoption  of  a  set  of  standards.  If  the  town 
adopts  the  gauge  of  the  nearest  large  city  it  will  probably  be  able 
to  get  its  supplies  more  quickly  when  they  are  needed  than  if  it 
selects  one  of  the  sets  specially  designed  by  some  engineer  anxious 
to  furnish  something  brand  new  for  each  plant  he  plans. 

In  using  the  tables  it  should  be  clearly  understood  that  with 
nozzles  of  1  inch  or  more  diameter  indicated  pressures  at  the  base 

FIRE-STKEAM  DATA  FOB  1^-lNCH  SMOOTH  NOZZLE. 


1 

5 

Best  fire 

1 

Hydrant  pressure  in  pounds  required  to  maintain  pressure 
at  base  of  play  pipe  as  per  column  1,  through 
2^  inch  hose  lines  mentioned. 

to 

jet. 

q 

m 

g 

8 

to 

50ft. 

103  ft. 

200  ft. 

300ft. 

400ft. 

500ft. 

a 

& 

1 

•*sT 

« 

tn 
q 
^ 

a 

j 

a 

to 
M 

q" 

to 
£ 

fl' 

1 

q' 

to 
& 

a 

<o 

o 

A 

o 

"3 

0> 

s 

d 

| 

® 

0> 

£ 

£ 

JQ 

a 

M 

I 

1 

O 

3 

2 

3 

^ 

1 

3 

M 

I 

« 

3 

1 

5     - 

84 

7 

6 

9 

7 

13 

9 

16 

1C 

20 

J2 

24 

13 

10 

18 

22 

119 

15 

12 

18 

14 

26 

17 

33 

2) 

40 

24 

48 

27 

15 

27 

31 

146 

22 

19 

27 

21 

38 

26 

49 

31 

60 

35 

71 

40 

20 

36 

38 

168 

29 

25 

36 

28 

51 

34 

66 

41 

80 

47 

95 

51 

25 

44 

44 

188 

36 

31 

45 

35 

64 

43 

82 

51 

101 

59 

119 

67 

30 

52 

50 

206 

44 

37 

55 

42 

77 

52 

99 

61 

121 

71 

143 

80 

35 

59 

54 

222 

51 

43 

64 

49 

89 

60 

115 

71 

141 

82 

166 

94 

40 

65 

69 

238 

58 

50 

73 

56 

102 

69 

131 

81 

161 

94 

190 

107 

45 

70 

63 

252 

65 

56 

82 

63 

115 

77 

148 

92 

181 

106 

214 

120 

50 

75 

65 

266 

72 

62 

91 

70 

128 

86 

164 

102 

201 

118 

238 

134 

55 

80 

69 

279 

80 

68 

100 

77 

140 

95 

181 

112 

221 

130 

262 

147 

60 

83 

72 

291 

87 

74 

109 

84 

103 

197 

122 

241 

141 

160 

65 

86 

75 

303 

94 

81 

118 

91 

166 

112 

214 

132 

2til 

153 

** 

174 

70 

88 

77 

314 

101 

87 

127 

179 

120 

230 

143 

165 

187 

75 

90 

79 

325 

109 

93 

136 

105 

191 

129 

246 

153 

177 

201 

£Q 

92 

81 

336 

116 

99 

145 

112 

24 

138 

283 

163 

\ 

188 

*m'm 

214 

85 

94 

83 

346 

123 

106 

154 

119 

217 

146 

173 

200 

227 

9i 

96 

85 

3o6 

130 

112 

164 

126 

155 

.... 

183 

[ 

212 

\*m 

241 

95 

98 

87 

366 

138 

1  8 

173 

133 

242 

163 

194 

224 

254 

100 

99 

89 

376 

145 

J24 

182 

140 

155 

172 

... 

201 

236 

Eighty  pounds  per  square  inch  is  now  considered  ihe  be«t  hydrant  pressure  for 
general  use;  100  pounds  should  not  be  exceeded  except  for  very  high  buildings.  If 
the  nozzle  is  much  higher  or  lower  than  the  hydrant,  allowance  for  difference  of  level 
must  be  made  on  hydrant  pressure;  10  feet  in  height  corresponds  to  4^6  pounds  water 
pressure. 

The  above  pressures  are  at  the  hydrant  head  while  str  am  is  flowing.  The  cone- 
spondingpump  or  reservoir  pressure  must  be  greater  thin  the  hydrant  pressure  by 
an  amount  equal  to  the  friction  loss  between  the  hydrant  head  and  pump  or 
reservoir 


262  WATER-WORKS    MANUAL. 

of  the  play  pipe  of  20  pounds  or  less  give  only  feeble  streams;  25 
to  30  pounds  -will  furnish  a  fair  stream,  35  to  45  pounds  a  good 
stream,  50  to  60  pounds  an  excellent  stream.  With  such  nozzles, 
pressures  of  65  pounds  or  more  at  the  base  of  the  play  pipe  make 
the  work  of  directing  the  stream  difficult  without  special  apparatus. 
When  nozzles  under  1  inch  in  diameter  are  used,  pressures  less 
than  25  pounds  will  give  streams  of  little  use  in  extinguishing  a 
fire  which  has  a  good  start,  although  they  may  be  of  assistance  in 
preventing  its  spread. 


FIRE-STREAM  DATA  FOR 


SMOOTH  NOZZLE. 


1 

of 

Best  fire 

3 

Hydrant  pressure  in  pounds  required  to  maintain  pressure 
at  base  of  play  pipe  as  per  column  1,  through 
214-inch  hose  lines  mentioned. 

1 

jet. 

a 

a 

1 

2 

P. 

1 

50ft. 

ICO  ft.         200  ft.         300  ft. 

400  ft. 

500  ft. 

1 

3 

« 

DO 

a 
5 

a 

1 

c 

o> 

,0 

• 

1 

B- 

1 

d 

t4 
o> 

a 

1 

•fH 

f] 

.g 

"3 

9 

J2 

© 

JS 

Q} 

S 

- 

V 

42 

d 

be 

"S 

O 

3 

& 

3 

PH 

c 

3 

& 

£ 

tf 

3 

tf 

_g 

& 

w 

tf 

5 

105 

8 

7 

11 

8 

17 

11 

23 

13 

28 

15 

34 

18 

10 

jg 

22 

148 

17 

14 

23 

16 

34 

21 

46 

26 

57 

31 

68 

36 

15 

28 

32 

181 

25 

21 

34 

24 

51 

32 

68 

39 

85 

47 

102 

54 

20 

37 

40 

209 

34 

27 

45 

32 

68 

42 

91 

52 

114 

62 

137 

72 

25 

46 

47 

234 

42 

34 

57 

40 

85 

53 

114 

65 

142 

77 

171 

90 

30 

53 

54 

256 

51 

41 

68 

49 

102 

63 

136 

78 

171 

93 

205 

108 

35 

60 

59 

277 

59 

48 

79 

57 

119 

74 

159 

91 

199 

109 

239 

126 

40 

67 

63 

296 

68 

55 

91 

65 

H6 

84 

182 

104 

227 

121 

273 

144 

45 

72 

67 

314 

76 

62 

102 

73 

153 

95 

205 

117 

256 

140 

162 

50 

77 

70 

331 

85 

68 

113 

81 

170 

106 

227 

130 

155 

180 

55 

81 

73 

347 

93 

75 

124 

89 

187 

116 

249 

143 

170 

19S 

60 

85 

76 

363 

102 

82 

136 

97 

204 

127 

156 

186 

216 

65 

88 

79 

377 

110 

89 

147 

105 

221 

137 

169 

\ 

201 

234 

70 

91 

81 

392 

118 

96 

158 

113 

238 

148 

182 

217 

252 

75 

93 

83 

405 

127 

103 

170 

121 

255 

158 

195 

232 

80 

95 

85 

419 

135 

110 

181 

129 

169 

208 

248 

85 

97 

88 

432 

144 

116 

192 

137 

179 

' 

221 

90 

99 

90 

444 

152 

123 

204 

145 

190 

234 

95 

100 

92 

456 

161 

130 

215 

154 

201 

'"_ 

217 

... 

.... 

100 

101 

93 

463 

169 

137 

22d 

162 

.... 

211 

261 

Eighty  pounds  per  square  inch  is  now  considered  the  best  hydrant  pressure  for 
general  use;  100  pounds  should  not  be  exceeded  except  for  very  high  buildings.  If 
the  nozzle  is  much  higher  or  lower  than  the  hydrant,  allowance  for  difference  of  level 
mupt  be  made  o a  hydrant  pressure;  10  feet  in  height  corresponds  to  4J^  pounds 
water  pressure. 

The  above  pressures  are  at  the  hydrant  head  while  stream  is  flowing.  The  corre- 
sponding pump  or  reservoir  pressure  must  be  greater  than  1  he  hydrant  pressure  by 
an  amount  equal  to  the  friction  loss  between  the  hydrant  head  and  pump  or 
reservoir. 


CHAPTEE    XX.— THE    WATER-WORKS    DEPARTMENT, 

In  the  preceding  pages  an  attempt  has  been  made  to  explain  the 
principles  which  should  govern  the  design  and  construction  of  a 
small  water  plant,,  but  there  remains  for  consideration  the  import- 
ant subject  of  paying  for  and  running  the  works.  If  the  plant  is 
the  property  of  a  private  corporation,  the  stockholders  have  pre- 
sumably undertaken  the  enterprise  after  full  consideration  of  this 
subject  from  an  investor's  point  of  view.  In  this  case  the  writer 
has  no  advice  to  offer.  If  the  plant  is  built  by  a  community,  how- 
ever, certain  hints  may  prove  useful. 

So  far  as  the  financial  problems  are  concerned,  no  definite  plans 
can  be  laid  until  the  state  laws  on  the  subject  have  been  studied. 
In  some  states  no  bonds  can  be  issued  without  a  sinking  fund  to 
extinguish  them  on  maturity,  and  the  life  of  such  bonds  is  fre- 
quently limited.  In  other  states  no  charge  can  be  made  for 
water  furnished  for  public  purposes,  which  lets  the  entire  expense 
fall  on  the  consumers.  It  is  therefore  necessary  to  bear  carefully 
in  mind  that  the  ideal  system  which  is  advocated  in  this  chapter 
may  be  impracticable  legally  in  some  places  in  some  respects,  and 
must  be  modified  so  as  to  be  as  nearly  equitable  to  everyone  as  the 
law  permits. 

An  issue  of  bonds  is  made  in  most  cases  to  cover  the  first  cost  of 
the  works.  The  duration  of  these  bonds  should  theoretically  cor- 
respond in  some  degree  with  the  life  of  the  plant,  and  here  it  is 
seen  at  once  that  real  estate,  reservoirs,  masonry  conduits  and  such 
portions  of  the  works  have  a  term  of  existence  to  which  the  pipes, 
and  still  more  the  pumping  machinery,  cannot  be  compared. 
Moreover  the  works  are  commonly  designed  to  meet  the  require- 
ments of  but  a  limited  period  of  years,  and  it  would  be  manifestly 
improper  to  issue  bonds  for  a  longer  period  than  the  assumed 
length  of  service  of  the  plant.  In  a  small  community,  the  bonds 
are  for  such  a  comparatively  small  sum  that  they  must  form  a 


264  WATER-WORKS    MANUAL. 

single  issue,  and  their  period  should  therefore  be  obtained  by 
weighing  all  the  influences  mentioned.  In  large  works  it  is  prefer- 
able to  follow  the  British  practice  of  issuing  long-period  bonds 
for  real  estate  and  other  permanent  investments  and  short  period 
bonds  for  the  perishable  portions  of  the  undertaking. 

After  the  plant  has  been  put  in  operation,  it  is  subject  to  a 
number  of  charges  of  different  classes.  The  most  important  are: 
1.  the  interest  on  the  bonds;  2,  the  sinking  fund  for  extinguishing 
the  bonds  at  maturity;  3,  the  cost  of  ordinary  repairs;  4,  a  charge 
for  the  depreciation  of  the  plant;  5,  the  expense  of  extensions;  6, 
the  operating  expense.  There  are  others  which  are  of  so  little  im- 
portance in  the  case  of  small  works  as  to  be  of  trifling  significance. 
In  raising  revenue  to  meet  these  expenses  it  is  important  to  con- 
sider the  purpose  of  the  works,  the  features  which  controlled  its 
cost,  and  the  uses  of  the  water. 

It  has  been  shown  in  Chapter  XIX.  that  the  capacity  of  the 
works  is  very  largely  influenced  by  the  demands  of  satisfactory 
fire  protection.  Estimates  made  by  a  number  of  engineers  show 
that  one-third  of  the  total  cost  of  a  plant  is  generally  spent  to  pro- 
vide enough  hydrants,  ample  mains  and  sufficient  pressure  to  meet 
such  requirements.  This  protection  is  afforded  to  the  property  of 
the  place  generally,  and  is  recognized  by  insurance  companies  in  es- 
tablishing their  rates.  It  is  therefore  just  that  a  considerable  por- 
tion of  the  revenue  of  the  water-works  department  should  be  met 
by  a  general  tax  on  account  of  this  service. 

A  certain  amount  of  water  is  also  used  in  schools  and  other 
public  buildings,  for  flushing  sewers,  sprinkling  streets  and  sim- 
ilar purposes,  all  of  which  are  for  the  general  good  of  the  com- 
munity and  should  be  paid  by  it.  The  amount  of  water  thus  used 
will  run  anywhere  from  5  to  15  per  cent,  of  the  whole  quantity. 
To  this  amount  should  be  added  the  leakage  from  street  mains, 
amounting  to  2,500  to  3,000  gallons  per  mile  of  pipe  daily  in  a 
well-built  and  carefully  maintained  plant.  Since  the  town  owns 
the  plant  this  leakage  should  be  charged  to  the  town  as  such, 
rather  than  against  the  percentage  of  the  people  who  may  be  con- 
sumers. 

The  plant  has  been  constructed  of  larger  capacity  than  the  pres- 
ent demand  for  water  and,  roughly  speaking,  a  quarter  of  its  total 
cost  has  been  expended  in  provisions  for  future  needs.  If  this  is 
taken  into  account  in  fixing  the  rates  for  water,  these  will  be  un- 


WATER-WORKS    MANUAL.  265 

duly  high  at  first,  when  they  should  be  as  low  as  equity  will  allow 
in  order  to  encourage  the  people  to  become  consumers  and  as  an 
inducement  to  industries  to  come  to  the  town. 

A  water  pipe  in  a  street  adds  an  appreciable  amount  to  the  value 
of  abutting  property,  just  as  do  improved  pavements  and  sewers. 
On  this  account  the  writer  believes  that  such  property  may  justly 
be  taxed  for  a  certain  proportion  of  the  cost  of  the  street  mains; 
say  an  amount  equal  to  the  cost  of  a  -i-inch  main  without  hydrants. 
The  extra  cost  of  larger  mains  and  of  the  reservoirs,  pumps  and 
other  portions  of  the  plant,  and  additions  to  them  from  time  to 
time,  should  be  considered  part  of  the  capital  expenditure  for  the 
works  as  a  whole. 

The  operating  expenditures  and  ordinary  repairs  should  be  paid 
by  all  the  consumers,  public  and  private,  since  they  are  incurred 
in  their  behalf  solely. 

The  provisions  for  sinking  fund  and  depreciation  are  usually 
combined  in  this  country,  for  the  reason  that  people  forget  a  sink- 
ing fund  is  for  paying  off  a  bonded  indebtedness  while  a  deprecia- 
tion fund  is  for  renewing  a  plant  when  it  is  worn  out.  It  is  mark- 
ed injustice  to  the  present  generation  to  require  it  pay  off  in 
twenty  or  thirty  years  the  bonds  it  issues  for  works  and  at  the 
same  time  accumulate  a  fund  for  the  construction  of  a  new  plant 
o^  which  a  future  generation  only  will  enjoy  the  benefits.  In 
states  where  a  sinking  fund  is  mandatory,  it  is  not  just  to  raise  a 
fund  for  depreciation.  The  result  of  such  laws  is  to  turn  over  to 
the  new  generation  "a  property  largely  free  from  debt,  but  in  a 
more  or  less  deteriorated  condition;  but  that  generation  may  use 
the  available  credit  and  taxing  power  of  the  city  to  renew  the  seri- 
ously deteriorated  portions  of  the  plant,  to  extend  the  water  ser- 
vice, and  to  enlarge  slightly  or  reinforce  the  more  substantial  por- 
tions of  the  property  in  anticipation  of  probable  future  require- 
ments." In  states  where  sinking  funds  are  not  required  by  law,  a 
real  depreciation  fund  may  be  created  and  the  old  bond  issues 
taken  up  by  new  ones.  In  this  way  the  water  department  always 
has  to  its  credit  funds  for  new  pumps  and  pipes  with  which  to 
replace  those  worn  out  in  service. 

In  ®ne  or  two  states,  water  departments  are  obliged  by  the  courts 
to  make  a  uniform  charge  for  water,  whether  it  is  used  in  large  or 
small  quantities.  The  injustice  of  this  is  beginning  to  be  generally 
understood.  It  is  based  on  the  assumption  that  it  costs  the  de- 


266  WATER-WORKS    MANUAL. 

partment  the  same  to  supply  a  large  quantity  of  water  to  a  single 
consumer  as  to  many  smaller  ones,  each  of  which  requires  as  much 
book-keeping  and  meter  reading  as  the  one  large  consumer.  The 
problem  of  adjusting  these  charges  on  an  equitable  basis  has  been 
solved  by  what  is  known  as  the  Madison  schedule,  devised  by  Mr. 
John  B.  Heim,  superintendent  of  the  Madison,  Wis.,  water  de- 
partment. In  this  schedule,  the  bills  of  each  consumer  are  made 
out  every  six  months  as  follows:  First  5,000  cubic  feet,  20  cents 
per  100  cubic  feet,  Over  5,000  and  up  to  20,000  cubic  feet,  $10 
for  first  5,000  cubic  feet  and  10  cents  for  each  additional  100  cubic 
feet.  Between  20,000  and  30,000  cubic  feet,  $25  for  the  first  20,- 
000  cubic  feet  and  5  cents  for  each  additional  100  cubic  feet. 
The  schedule  runs  much  higher,  but  the  charges  are  made  in  the 
same  manner.  The  minimum  charge  per  six  months  is  $2.^5. 

A  caution  should  be  given  against  the  very  common  but  very 
bad  schedule  which  reads  about  as  follows:  For  quantities  under 
5,000  cubic  feet,  20  cents  per  100  cubic  feet.  For  quantities  be- 
tween 5,000  and  10,000  cubic  feet,  10  cents  per  100  cubic  feet, 
etc.  Such  a  schedule  is  a  direct  invitation  to  intentional  waste 
under  certain  circumstances.  If  a  consumer  finds  just  before  the 
meter  reader  is  due  that  he  has  taken  4,000  cubic  feet,  costing  him 
$8,  it  will  be  to  his  advantage  to  leave  his  fixtures  open  until 
^000  cubic  feet  are  registered;  for  if  the  meter  reader  finds  the 
consumption  has  been  5,500  cubic  feet  the  bill  will  be  but  $5. 50.  No 
such  juggling  is  possible  with  the  Madison  schedule,  and  it  is  not 
surprising  to  find  it  growing  rapidly  in  favor.  The  actual  charge 
to  be  made  per  100  cubic  feet  or  gallons  depends,  of  course,  on  the 
cost  of  the  water  to  the  department  and  the  percentage  of  the  total 
expense  of  the  works  which  are  met  by  the  water  rates. 

CHECKING  WASTE. 

When  water-works  were  first  built  in  this  country,  there  was  com- 
paratively little  difference  between  the  various  houses  of  a  town 
and  the  water  rates  were  made  uniform  on  each  building  or  de- 
pendent on  the  number  of  people  it  sheltered,  or  on  its  height  and 
frontage.  Such  a  plan  answered  fairly  well  for  a  time,  but  it  was 
finally  learned  by  observation  that  there  was  a  difference  in  the 
amount  of  water  taken  in  houses  holding  the  same  number  of  per- 
sons. The  next  step  was  to  make  the  charge  for  water  depend- 
ent on  the  number  and  variety  of  the  fixtures.  This  was  unques- 
tionably a  step  forward,  for  it  was  then  an  easy  matter  to  ascer- 


WATER-WORKS    MANUAL.  267 

tain  roughly  the  amount  of  water  probably  taken  for  legitimate 
purposes  from  each  type  of  fixture,  for  breweries  and  other 
manufacturing  purposes,  masonry,  etc.  In  this  way  schedules 
were  prepared  from  which  charges  were  made  out  with  somewhat 
nearer  approach  to  justness  than  by  the  primitive  methods. 

There  was  a  marked  difference  in  the  quality  of  fixtures  after  a 
time,  and  in  the  workmanship  of  the  plumbers  who  placed  them 
in  the  buildings.  Some  fixtures  were  found  to  be  very  wasteful 
of  water;  the  total  waste  became  so  great  as  to  make  it  necessary 
to  build  new  works  long  before  they  were  really  needed,  and  in 
some  cities  the  pressure  on  the  street  mains  was  inadequate  for  fire 
protection.  The  trouble  was  the  same  in  Great  Britain  as  here, 
but  the  methods  of  overcoming  it  which  were  first  introduced  in 
the  two  countries  differed  considerably. 

The  house-to-house  inspection  practiced  in  the  United  States 
and  Great  Britain  proved  fairly  successful  in  small  communities 
in  determining  the  number  of  fixtures  and  their  condition  at  the 
time  of  the  inspector's  visit.  It  did  not  accomplish  very  much, 
however,  because  a  poor  fixture  would  not  be  transformed  into  a 
good  one  just  because  a  representative  of  a  water  department  look- 
ed at  it,  nor  were  the  occupants  of  the  house  always  as  careful 
to  keep  the  water  from  running  to  waste  as  when  an  official  was 
paying  his  visit. 

The  remedy  for  poor  plumbing  adopted  in  Great  Britain  was  to 
require  all  fixtures  to  pass  an  official  test  and  be  stamped  before 
they  could  be  used,  and  even  then  they  had  to  be  placed  in  ac- 
cordance with  prescribed  rules.  This  plan  is  so  far  at  variance 
with  American  character  that  it  was  never  introduced  into  the 
United  States,  to  the  writer's  knowledge,  although  it  proved  a 
comparative  success  in  Great  Britain.  It  is  described  in  detail  in 
the  book  entitled  "Water- Waste  Prevention,"  written  by  Mr. 
Henry  C.  Meyer  nearly  twenty  years  ago,  after  a  personal  study  of 
the  results  accomplished  by  it.  This  book  is  still  the  standard  au- 
thority on  water  waste  subjects. 

It  is  probable  that  the  importance  of  preventing  the  waste  of 
water  was  first  brought  prominently  before  the  American  public 
by  this  work,  which  appeared  originally  as  a  series  of  articles  in 
"The  Engineering  Record."  A  few  American  cities,  notably 
Providence,  had  undertaken  to  check  waste  by  the  use  of  meters, 
but  these  devices  were  then  in  their  infancy,  they  were  compara- 


268  WATER-WORKS    MANUAL. 

tively  expensive,  and  people  who  had  become  accustomed  by  the 
older  methods  of  distribution  to  regard  water  as  something  nearly 
free  as  air,  raised  an  unjust  opposition  to  their  use. 

The  extensive  introduction  of  water  closets,  the  increased  var- 
iety and  number  of  fixtures  in  houses,  and  the  manufacture  of  the 
flimsiest  sort  of  faucets  and  cocks  soon  made  it  apparent  that 
some  means  had  to  be  taken  to  prevent  waste.  House-to-house 
inspection  was  only  slightly  successful  as  a  rule,  and  the  practice 
of  testing  and  stamping  fixtures  could  not  be  introduced  here,  even 
were  it  desirable,  on  account  of  trade  opposition  too  powerful  to 
overcome.  The  consequence  was  the  adoption  of  regulations  in 
many  cities  authorizing  the  water  department  to  place  meters  on 
the  service  pipes  of  each  building  where  waste  continued  after  the 
occupants  had  been  notified  to  check  it.  The  general  passage  and 
enforcement  of  these  regulations  gave  an  impetus  to  the  manu- 
facture of  meters,  old  types  were  improved,  new  ones  developed, 
and  the  result  is  that  to-day  the  sale  of  water,  like  that  of  gas, 
can  be  carried  on  justly  only  by  metering  the  services.  This  is 
now  definitely  determined  by  actual  experiments,  of  which  but  one 
of  many  need  be  mentioned  here.  It  is  stated  exactly  as  de- 
scribed in  the  annual  report  of  the  Lowell,  Mass.,  Water  Board 
for  1894. 

"A,  B,  C,  etc.,  represent  certain  pieces  of  property  in  Lowell. 
On  this  property  (paying  annual  rate  charges  at  the  time),  and  un- 


§g» 

I-H  .5 


A.    5  tenen: 
B.  12 
(  4  offices 
C.  1  2  halls 
(  3  stores 
D.    5  tenen 
E.     3 
F.     9 
G.  12 
H.  16 
I.      3 
J.     4 
K.     5 

tents  

W 
...       24,000 

$44.00 
51.00 

79.00 

57.00 
26.00 
73.00 
123.00 
93.00 
31.00 
40.00 
40.50 

$33.60 

47.88 

174.37 

120.40 
25.20 
74.72 
246.42 
81.76 
68.77 
151.00 
194.88 

fi 
$0.183 
0.149 

0.067 

0.066 
0.144 
0.136 
0.069 
0.159 
0.063 
0.033 
0.030 

34  200 

!( 

.  .  .     116,250 

i 

lents 

86  025 

18,000 

53  375 

176  Oil 

58  400 

49  125 

.  .  .     107,877 

139.200 

beknown  to  owner  as  far  as  possible,  a  meter  was  attached  during 
the  summer  months.     The  quantity  of  water  actually  being  used 


WATER-WORKS    MANUAL.  269 

was  thus  ascertained.  From  this  fact  and  the  yearly  rate  paid,  the 
results  in  the  table  were  obtained." 

The  last  column  contains  the  pith  of  the  whole  matter.  Be- 
cause of  the  absolute  inaccuracy  of  any  schedule  based  on  the 
number  and  class  of  fixtures,  the  city  was  being  paid  3  cents 
per  100  cubic  feet  by  one  man,  and  18.3  cents  by  another,  or 
more  than  six  times  as  much.  This  was  an  injustice  between  con- 
sumers. The  city  itself  was  sometimes  paid  more,  but  generally 
very  much  less  than  the  value  of  the  service  it  rendered. 

These  figures  of  actual  results,  easily  supplemented  by  many 
more  of  the  same  tenor,  explain  the  value  of  meters  in  checking 
waste.  Some  people  will  be  careful  because  they  are  intelligent 
and  understand  that  carelessness  and  degeneration  go  hand  in 
hand,  others  are  careful  because  they  wish  to  save  the  expense  of 
carelessness,  and  others  will  not  be  careful  under  any  conditions. 
If  water  is  not  supplied  by  meter  the  careful  .people  have  to  pay 
for  their  own  supplies  and  most  of  the  waste  of  the  others;  if 
meters  are  used,  the  first  two  classes  pay  for  only  the  water  they  use 
and  the  last  class  pays  for  what  it  uses  and  wastes,  just  as  it  should 
do.  The  cost  of  operating  the  plant  is  kept  down,  street  main 
pressures  are  kept  up,  and  water  can  be  supplied  at  a  low  price. 
Let  any  other  system  be  introduced  and  waste  will  ensue,  oper- 
ating expenses  mount  up  rapidly,  fire  protection  will  become  dif- 
ficult, and  the  charges  for  water  will  be  high.  It  is  very  probable 
that  the  general  introduction  of  meters  to-day  in  cities  where  they 
are  not  used,  would  check  waste  to  an  extent  more  than  paying 
for  their  cost  in  a  few  years. 

The  statement  that  the  universal  use  of  meters  in  a  small  com- 
munity is  prohibited  by  their  cost  is  not  true.  If  water  is  sold 
from  the  outset  by  meter  measurement  the  careful  habits  which 
scon  become  second-nature  result  in  the  prevention  of  enough 
waste  to  save  in  operating  expenses  in  a  few  years  the  cost  of  the 
meters.  It  is  probable  that  much  of  the  trouble  attending  the 
introduction  of  these  appliances  has  been  due  to  the  conditions 
of  their  use.  Instead  of  their  being  purchased  by  the  consumer 
it  will  be  found  more  satisfactory  for  the  water  department  to  buy 
them  in  quantities.  An  advertisement  in  "The  Engineering 
Record"  asking  for  bids  on  lots  of  a  hundred  or  more  meters  will 
be.  read  by  every  manufacturer  in  the  country  and  probably  re- 
sult in  placing  a  contract  at  a  considerably  lower  figure  than  can 


270  WATER-WORKS    MANUAL. 

be  obtained  by  buying  a  few  meters  at  a  time,  as  needed,  through 
a  local  plumber. 

The  water  department  should  charge  each  consumer  about  one 
dollar  annually  for  the  setting  and  use  of  the  meter,  including 
repairs  and  renewal  when  it  wears  out.  This  sum  is  just  to  the 
consumer  and  the  department,  and  keeps  the  control  of  the 
meters  in  the  hands  of  the  city.  In  case  a  consumer  wishes  to 
have  a  meter  tested,  it  should  always  be  done  provided  he  signs 
an  agreement  to  pay  the  cost  of  the  work  if  the  meter  is  found 
to  be  accurate  or  to  register  less  than  the  amount  of  water  which 
flows  through  it. 

So  far  as  the  writer  has  been  able  to  ascertain  but  one  attempt 
was  ever  made  to  ascertain  on  a  large  scale  the  amount  of  water 
used  by  various  fixtures.  This  was  done  at  Newton,  Mass.,  by 
Mr.  J.  Whitney,  and  reported  to  the  New  England  Water- Works 
Association.  At  the  time  the  investigation  was  made,  there  were 
no  sewers  in  the  town,  and  as  all  water  was  supplied  through 
meters  there  was  every  inducement  to  curtail  waste.  There  were 

019  family  supplies  studied,  the  average  family  comprising  five 
persons.     This  average  family  used   12,046  gallons  during  the 
year  from  the  first  or  kitchen  faucet,  and  this  amount  was  used 
as  a  standard  in  rating  the  amount  used  by  the  remaining  fixtures. 

Additional  faucets  were  estimated,  as  a  result  of  the  investiga- 
tion, to  add  20  per  cent,  each  to  the  consumption,  the  first  bath- 
tub 75  per  cent.,  the  second  bath-tub  15  per  cent.;  the  first  water- 
closet  90  per  cent.,  the  second  water-closet  40  per  cent.,  set-tubs 

20  per  cent.,  and  hose  90  per  cent.     The  studies  showed  that 
faucets  should  be  charged  75  per  cent,  of  the  family  rate  if  used 
in  groceries,  50  per  cent,  in  dry  goods  stores,  75  per  cent,  in  mar- 
kets, dentists'  offices  and  barber  shops,  300  per  cent,  in  fish  stores, 
250  per  cent,  in  photographic  studios,  and  the  same  charge  for 
pharmacies  as  for  dwellings.     Water-closets  are  rated  the  same  in 
business  as  in  dwelling  houses.     The  school  rates  for  drinking 
water  were  placed  equal  .to  the  domestic  first  faucet  rate  for  each 
200  pupils,  and  three  times  the  family  rate  in  the  case  of  water 
closets.     Church  rates  were  found  to  be  equitable  when  placed  at 
half  those  for  families.     In  power  plants  running  ten  hours  daily 
it  was  found  that  a  suitable  charge  would  be  130  per  cent,  of  the 
family  faucet  rate  per  horse-power  of  the  boilers.     Laundries  were 
found  to  use  per  person  about  three  times  the  first  fixture  con- 


WATER-WORKS    MANUAL.  271 

sumption  of  families.  In  greenhouses  a  fair  charge  seemed  to  be 
85  per  cent,  of  the  faucet  rate  where  the  establishment  was  for 
forcing  vegetables  and  the  full  faucet  rate  where  it  was  run  by 
florists.  In  the  case  of  livery  stables  it  was  found  desirable  to 
charge  20  per  cent,  of  the  faucet  rate  for  each  horse,  when  car- 
riages are  not  washed,  50  per  cent,  per  horse  where  the  carriages 
are  washed  without  hose,  and  75  per  cent,  if  hose  is  used.  In  pri- 
vate stables,  the  full  faucet  rate  was  recommended  for  each  horse. 
In  trucking  stables,  one-third  of  the  family  rate  seemed  to  be  the 
proper  charge  for  each  horse,  because  so  little  washing  of  wagons 
is  done. 

Where  families  contained  more  than  five  members  it  was  found 
that  each  additional  person  increased  the  consumption  about  7 
per  cent. 

In  view  of  the  fact  that  such  a  schedule  is  the  best  the  writer 
has  found  as  the  result  of  correspondence  and  personal  inquiry 
for  a  number  of  years,  he  considers  its  use  in  place  of  meters  by 
any  new  works  a  deplorable  step  backward  which  will  be  deeply 
regretted. 

KEEPING   UP   THE   WORKS. 

The  problems  which  arise  to  perplex  the  superintendent  of  a 
water  plant  are  so  varied  that  but  a  few  of  the  most  common  can 
be  noticed  here. 

Where  driven  wells  furnish  the  supply  it  is  by  no  means  un- 
usual to  have  trouble  with  air  when  the  pumps  are  running  at 
their  full  capacity.  If  there  is  no  air  chamber  on  the  suction  pipe, 
with  a  pump  to  remove  the  air,  the  introduction  of  such  an  ap- 
paratus will  prove  probably  beneficial.  The  present  practice  is  to 
place  one  in  the  pumping  station,  as  shown  in  Figure  31,  but 
formerly  they  were  often  omitted.  If  the  air  chamber  fails  to 
remedy  the  pounding  of  the  pumps,  it  is  possible  that  some  of  the 
wells  may  be  so  shallow  as  to  yield  more  air  than  water  during 
periods  of  heavy  draft,  or  the  piping  may  have  been  injured.  If 
each  well  has  a  valve  by  which  it  can  be  shut  off,  it  will  generally 
be  possible  to  locate  the  trouble  by  shutting  off  one  well  after 
another  until  that  which  causes  the  trouble  has  been  found. 
Slight  leaks  in  the  joints  can  be  remedied  by  calking  if  they  are 
lead  or  painting  with  thick  asphalt  paint  if  they  are  flange. 

Anchor  ice  is  one  of  the  most  annoying  troubles  of  works  draw- 
ing water  from  rivers  and  ponds.  What  it  means  can  be  best 


272  WATER-WORKS    MANUAL. 

shown  by  describing  a  couple  of  instances  of  its  occurrence.  The 
first  case  was  reported  by  the  late  James  B.  Francis  as  taking  place 
in  a  1,750,000-gallon  reservoir  at  St.  John,  N.  B.,  in  which  the 
water  had  a  maximum  depth  of  18  feet.  At  the  time  of  the 
trouble  there  was  about  8  feet  of  water  and  ice  in  the  basin,  and 
the  surface  was  covered  with  ice  except  for  about  250  square  yards 
of  open  water  directly  over  the  inlet  pipe.  "On  the  evening  of 
December  8th,  1882,"  Mr.  Francis  said,  "the  supply  of  water  to 
this  district  suddenly  ceased,  and  so  continued  for  a  short  time 
until  other  connections  were  opened.  On  the  following  morn- 
ing a  hole  was  cut  in  the  ice,  which  was  about  6  inches  thick,  im- 
mediately over  the  outlet  pipes,  where  a  mass  of  ice  was  found, 
which  is  described  as  a  kind  of  slush  or  minute  particles  of  con- 
gealed water;  on  prying  upon  it,  it  floated  up,  and  the  bottom  of  it 
was  exactly  the  shape  of  the  strainer  of  the  outlet  pipe,  showing 
that  it  rested  upon  it  and  completely  closed  up  the  outlet.  The 
strainer  is  a  copper  rose,  perforated  with  holes  about  J-inch  in 
diameter,  the  marks  of  which  appeared  on  the  ice.  The  whole 
column  when  taken  out,  or  as  much  of  it  as  would  hold  together, 
was  about  the  size  of  a  barrel,  and  was  composed  of  minute  par- 
ticles of  ice,  all  standing  on  end,  firmly  adhering  to  each  other." 
Mr.  Francis  concluded  that  the  "ice  which  closed  the  strainer 
formed  on  the  open  water  over  the  inlet  pipe,  was  carried  under 
the  ice  by  eddies  and  currents,  and  continued  in  motion  until  it 
reached  the  strainers."  The  essential  conditions  for  the  forma- 
tion of  anchor  ice,  are,  he  held,  that  the  temperature  of  the 
water  be  at  the  freezing  point,  and  that  of  the  air  below  that  point; 
the  surface  of  the  water  must  be  exposed  to  the  air,  and  there  must 
be  a  current  in  the  water.  The  ice  is  formed  in  small  needles  on 
the  surface,  which  are  carried  to  the  bottom  by  eddies.  The  little 
particles  of  ice  are  so  small  that  when  pressed  against  a  stone  or 
stick  at  the  bottom,  the  tendency  to  adhere  to  the  object  on  ac- 
count of  regelation  is  much  greater  than  the  exterior  force  tending 
to  move  the  particle  along.  Other  particles  are  caught  in  the 
same  manner  until  the  mass  is  produced  which  is  called  anchor 
ice.  The  adherence  of  the  ice  to  the  bed  of  the  stream  is  be- 
lieved to  take  place  downstream  from  the  place  where  it  is  formed, 
several  miles,  in  fact,  in  the  case  of  large  rivers. 

The  Water  Department  of  Ottawa,  Canada,  was  troubled  with 
this  ice  for  many  years.     The  pumps  are  driven  by  turbines  which 


WATER-WORKS    MANUAL.  273 

became  so  clogged  as  to  be  stopped  completely  at  times.  One  of 
the  most  serious  difficulties  occurred  in  December,  1894,  when  the 
entire  station  was  rendered  unserviceable  for  6J  hours.  It  was 
shortly  after  midnight  when  the  men  on  duty  first  became  aware 
of  the  presence  of  the  ice.  The  wheels  began  to  revolve  with  less 
speed,  but  the  slowing  down  had  hardly  been  noticed  before  they 
all  came  to  a  sudden  stop.  Every  man  was  put  to  work  who  could 
be  made  useful,  and  by  7  o'clock  the  first  wheel  began  to  move 
slowly.  An  hour  later  a  second  wheel  was  started,  and  at  9  o'clock 
a  third  commenced  turning  and  after  half  an  hour  of  jerky  motion 
settled  down  to  steady  work  at  about  half  speed.  The  explanation 
of  the  trouble  given  by  Mr.  Robert  Surtees,  then  city  engineer, 
was  that  under  certain  atmospheric  conditions,  not  particularly 
governed  by  the  degree  of  cold,  and  when  a  wind  is  blowing,  the 
little  wavelets  thus  formed  are  frozen.  The  spicules  of  ice  are 
carried  down  and  pass  through  the  gratings  into  the  wheels, 
where  they  lodge.  He  noticed  this  condition  never  existed  dur- 
ing the  daytime,  and  apparently  ceased  with  the  slight  change  in 
the  atmosphere  caused  by  the  rising  sun.  Attempts  were  made 
without  success  to  keep  the  ice  from  the  wheels  by  placing  ever- 
green brush  in  front  of  the  screen  protecting  them  from  sticks 
and  other  obstructions. 

The  most  successful  method  of  dealing  with  slush  ice  with 
which  the  writer  is  familiar  was  originated  by  Mr.  John  F.  Ward 
while  he  was  in  charge  of  the  water- works  of  Jersey  City,  1ST.  J. 
So  much  ice  of  this  sort  collected  at  the  screens  of  a  reservoir 
that  on  one  or  two  occasions  the  screens  were  broken.  He  made 
a  small  raft  of  12xl2-inch  timbers  which  happened  to  be  handy 
and  moored  it  in  front  of  the  screens.  This  prevented  the  trou- 
ble entirely.  His  explanation  of  its  success  is  that  in  consequence 
of  the  length  of  the  line  around  the  edge  of  the  raft  being,  say, 
four  times  the  width  of  the  screen,  the  force  available  to  draw 
in  the  ice  is  reduced  in  the  same  proportion.  The  ice  collects  in 
a  mass  around  the  raft  and  its  cohesion  is  so  great  that  the  current 
is  not  strong  enough  to  suck  it  under  the  timbers  to  the  screen. 

The  method  of  dealing  with  anchor  ice  at  submerged  intakes 
was  described  in  Chapter  XV. 

Hydrants  are  also  a  source  of  anxiety  during  the  winter  on  ac- 
count of  their  liability  to  freeze.  The  best  way  of  preventing  the 
trouble  is  to  use  long  ones,  so  that  the  connection  between  them 


274  WATER-WORKS    MANUAL. 

and  the  street  main  will  be  well  below  the  frost  line.  They  usually 
have  a  drip  hole  so  they  can  be  drained  into  the  nearest  sewer,  but 
if  there  are  no  sewers  and  the  bottom  of  the  hydrant  is  surround- 
ed by  any  other  material  than  very  porous  sand  or  gravel  it  will 
probably  prove  advisable  to  plug,  the  hole.  If  this  is  not  done  the 
water  will  collect  around  the  bottom  of  the  hydrant  and  may 
freeze  it.  Such  plugged  hydrants  must,  of  course,  be  kept  free 
Irom  water  by  a  hand  pump,  which  should  be  used  immediately 
after  every  fire  and  at  any  other  time  an  inspection  shows  it  to  be 
necessary.  No  matter  how  well  the  hydrants  are  drained  they 
should  be  watched  carefully  during  freezing  weather,  and-  thawed 
out  whenever  necessary  by  means  of  a  portable  boiler  furnished 
with  a  rubber  hose  by  which  a  jet  of  steam  can  be  turned  into  the 
barrels. 

At  Bay  City,  Mich.,  the  hydrants  in  the  outlying  parts  of  the 
city  occasionally  gave  considerable  trouble  by  freezing,  where  there 
was  no  adequate  sewerage,  and  the  ground  water  rose  to  the  frost 
level.  Mr.  E.  L.  Dunbar  found  the  most  effective  method  of  deal- 
ing with  such  hydrants  was  to  bank  them  in  autumn  as  high  as 
possible,  leaving  room  for  the  firemen  to  couple  to  the  nozzles. 
They  were  frequently  examined  through  the  winter,  and  if  ice 
began  to  form  on  them  they  were  warmed  thoroughly  with 
steam  or  hot  water,  which  usually  protected  them  for  several  days. 

In  very  cold  climates  particular  precautions  have  to  be  taken 
with  the  tops  of  the  hydrants.  At  Fredericton,  N".  B.,  Mr.  Alex- 
ander Burchill  reported  in  1892  that  the  principal  trouble  was  with 
the  screw  and  stuffing  box.  He  avoided  it  by  taking  off  the  caps  of 
the  hydrants  every  fall  and  running  a  clamp,  made  specially  for 
the  purpose,  through  the  opening  of  the  hydrant.  It  was  secured 
there  and  held  the  valve  rod  firmly  in  place.  The  stuffing  box,  fe- 
male screw  and  other  parts  were  then  taken  out,  wiped  dry  and 
clean,  covered  with  kerosene  and  returned  to  their  places,  after 
which  the  clamp  was  taken  out.  The  stuffing  box  packing  was 
kept  soft  all  winter  by  occasionally  saturating  it  with  kerosene, 
and  no  hydrant  was  opened  during  the  winter  if  it  could  be 
avoided.  As  soon  as  water  was  turned  off  after  a  fire,  the  hydrant 
was  at  once  attended  to,  and  the  stuffing  box  and  other  parts  taken 
out,  dried  and  oiled.  At  Woodstock,  in  the  same  province,  Mr. 
Donald  Monro  started  the  tops  of  hydrants  which  stuck  by  means 
of  circular  pieces  of  canvas,  12  inches  in  diameter  and  soaked  in 


WATER-WORKS    MANUAL.  275 

paraffine.  One  of  these  was  placed  on  top  of  a  hydrant,  there 
being  a  hole  to  allow  the  nut  to  come  through,  and  then  set  on 
fire.  The  heat  always  started  the  parts. 

Frozen  services  are  generally  thawed  out  by  means  of  small 
pipes  inserted  in  them  from  within  the  house.  Steam  is  turned 
into  the  pipes  and  the  ice  melted  out  in  this  manner.  It  is  gen- 
erally necessary  to  start  the  ice  only,  as  the  pressure  of  the  water 
will  force  most  of  it  out.  In  some  places,  as  in  Providence,  the 
water  department  has  a  portable  steam  boiler  from  which  run  a 
number  of  small  rubber  pipes.  A  long  1-inch  iron  pipe  is  attach- 
ed to  each  hose  and  furnished  with  a  handle  near  the  point  of  con- 
nection. One  of  the  iron  pipes  is  held  vertically  over  the  service 
pipe  to  be  thawed  out,  near  its  junction  with  the  street  main. 
Steam  is  then  turned  on  and  the  ground  is  quickly  thawed,  so 
that  the  pipe  can  be  forced  down  by  the  handle  like  an  auger  to 
the  service  pipe.  The  steam  then  thaws  out  the  pipe,  and,  as  two 
or  three  lines  of  hose  can  be  operated  at  once,  it  generally  requires 
but  15  to  20  minutes  to  free  a  pipe.  The  most  unique  method  of 
thawing  services  with  which  the  writer  is  acquainted  was  described 
as  follows  by  Mr.  C.  K.  Walker,  of  Manchester,  N.  H.:  "We  have 
tried  various  ways,  and  now  we  dig  a  hole  2  feet  deep  and  about  3 
feet  across;  we  put  in  some  lime  and  pour  on  some  water,  go  home 
and  go  to  bed,  and  next  morning  everything  is  all  thawed  out." 

The  method  of  thawing  pipes  by  electricity,  which  was  intro- 
duced at  Madison,  Wis.,  in  the  winter  of  1898-99  by  Messrs.  Jack- 
son and  Wood  of  the  University  of  Wisconsin,  is  one  of  the  most 
important  improvements  in  water-works  practice  in  recent  years. 
The  directions  for  using  it,  issued  by  the  university,  are  as  follows: 

The  current  which  is  required  for  satisfactorily  thawing  service 
pipes  up  to  1^  inches  in  diameter  is  from  200  to  300  amperes.  The 
source  of  current  should  have  a  pressure  of  not  less  than  50  volts. 
Where  electric  light  lines  carrying  alternating  currents  are  avail- 
able, a  transformer  or  transformers  in  parallel  may  be  used  as  a 
source  of  current.  It  is  very  important  that  direct  connection  of 
pipes  to  house  lines  be  avoided,  on  account  of  the  danger  of  fire 
in  which  the  house  is  placed  by  such  a  connection.  Where  alter- 
nating currents  are  not  available  continuous  current  feeder  lines 
may  be  used,  but  these  should  be  entirely  separated  from  the  dis- 
tributing network  of  conductors. 

Where  an  alternating  circuit  is  used  a  fuse  box  should  be  placed 


276  WATER-WORKS    MANUAL. 

in  each  wire  leading  from  the  feeders  to  the  transformer  and  an 
ammeter  connected  in  one  of  these  lines.  The  secondary  leads  or 
wires  from  the  transformer  should  be  No.  3  B.  &  S.  gauge  or 
larger.  In  making  connection  to  the  pipes,  one  of  the  secondary 
leads  should  be  taken  into  the  house  to  which  the  frozen  service 
runs,  and  contact  made  by  some  form  of  metal  clamp  or  simply 
winding  the  conductor  tightly  about  a  faucet  or  exposed  water 
pipe.  The  other  secondary  lead  should  be  put  in  contact  with  the 
water  system  outside  of  the  house  in  a  similar  manner.  This  con- 
tact may  be  made  at  a  hydrant,  an  adjoining  service  box,  or  a 
pipe  in  a  neighboring  house.  Where  there  are  two  houses  near 
together,  each  with  frozen  service  pipes,  the  two  secondary  leads 
may  be  connected  to  the  pipes  within  these  houses  and  both  frozen 
service  pipes  thawed  out  at  once. 

While  the  thawing  process  is  going  on,  the  faucet  should  be  open 
in  the  house  to  which  the  service  pipe  runs.  In  one  of  the  sec- 
ondary leads  should  be  inserted  a  water  resistance  which  may  con- 
sist of  a  bucket  of  water  containing  a  bowlful  of  salt  and  two  sheet- 
iron  or  copper  plates,  to  which  the  ends  of  the  severed  lead  are  at- 
tached. This  serves  to  control  the  current.  When  all  connec- 
tions are  made,  the  plates  are  placed  in  the  bucket  and  are  then 
moved  towards  each  other  until  the  ammeter  records  a  proper  cur- 
rent. If  the  primary  pressure  is  1,000  volts  and  the  secondary 
pressure  50  volts,  the  current  should  ordinarily  approach  15  am- 
peres. If  the  primary  pressure  is  2,000  volts  and  the  secondary 
pressure  50  volts,  the  ammeter  reading  should  ordinarily  approach 
7J  volts. 

Water  does  not  ordinarily  begin  to  flow  in  less  than  10  minutes, 
but  it  may  be  nearly  an  hour  before  it  starts.  The  frozen  pipes 
are  often  split  by  the  ice  and  begin  to  leak  as  soon  as  they  are 
thawed,  so  it  is  desirable  to  have  a  plumber  where  he  can  be 
readily  called  in  case  such  a  leak  is  discovered. 

The  water  pressure  at  the  hydrants  of  some  plants  is  tested  every 
spring  and  fall  by  means  of  a  pressure  gauge  previously  examined 
with  care  to  insure  its  accuracy.  Such  an  inspection  not  only  fur- 
nishes a  good  indication  of  the  number  of  fire  streams  which  may 
be  reasonably  expected,  but  also  reveals  any  leaks  in  mains.  For 
example,  an  inspection  of  this  sort  at  St.  John,  X.  B.,  showed  a 
fall  of  10  pounds  at  one  hydrant  below  the  reading  taken  six 
months  before.  A  search  was  made  and  a  leak  was  finally  found 


WATER-WORKS  MANUAL. 


277 


in  a  broken  4-inch  pipe  under  an  old  wharf.  This  was  repaired, 
but  the  gauge  still  showed  a  diminished  pressure.  Another  search 
was  made,  which  revealed  a  second  broken  4-inch  pipe;  when  this 
was  repaired,  the  pressure  returned  to  its  normal  amount. 

In  towns  where  there  is  an  electric  railway  with  tracks  in  the 
same  streets  as  the  water  pipes,  the  latter  are  in  danger  of  damage 
by  electrolysis,  which  pits  and  eats  through  the  metal  as  shown  in 
Figure  53.  This  engraving  was  made  from  a  photograph  of  a  pipe 
destroyed  by  this  action  at  Zanesville,  Ohio. 

There  is  nothing  whatever  mysterious  about  electrolysis.  It  is 
one  of  the  elementary  laws  of  electricity  that  when  an  electric  cur- 
rent can  pass  by  two  circuits  or  routes  to  a  given  point,  the  cur- 
rent will  be  split  into  two  parts  in  reversed  proportion  to  the 
resistance  of  the  routes;  the  greater  part  will  pass  by  the  route  of 
least  resistance  and  the  smaller  part  by  the  other.  In  the  case  of 


FIGURE  53.— THE  RESULT  OF  ELECTROLYSIS. 

the  ordinary  overhead  trolley  road,  the  electricity  is  sent  from  the 
power  station  through  the  overhead  wires  to  the  trolley  of  the  car. 
It  passes  from  the  trolley  through  the  wiring  and  motors  of  the 
car  to  the  rails,  and  then  nominally  through  the  rails  back  to  the 
power  house.  In  order  that  the  rails  may  return  the  current  satis- 
factorily, their  adjoining  ends  are  bonded  by  copper  wires  and  are 
very  often  connected  to  copper  wires  laid  in  the  roadbed  and  run- 
ning to  the  switchboard  of  the  power  station.  The  earth,  par- 
ticularly where  it  is  moist,  is  a  fair  electrical  conductor,  and  the 
water  and  gas  pipes  buried  in  it  also  offer  little  resistance  to  cur- 
rents. Hence  it  frequently  happens  that  a  considerable  portion  of 
the  current  leaves  the  rails,  passes  through  the  earth  and  travels 
along  a  buried  pipe  until  it  reaches  a  point  where  the  rails  again 
offer  a  route  of  smaller  resistance.  At  this  place  some  of  the  cur- 
rent will  leave  the  pipes  and  go  back  to  the  rails. 


278  WATER-WORKS  MANUAL. 

Where  an  electric  current  leaves  a  metallic  conductor  and  passes 
through  earth  or  a  liquid  to  another  metallic  conductor,  the  metal 
of  the  first  conductor  is  eaten  away,  a  phenomenon  utilized  to 
electroplate  various  objects;  where  an  electric  current  leaves  a 
water  pipe  the  metal  is  eaten  away  in  just  this  manner.  It  is 
obvious  that  the  remedy  is  to  keep  the  current  from  the  pipes  as 
far  as  possible,  or  where  this  is  impracticable  to  return  it  from  the 
pipes  by  heavy  metallic  conductors  which  will  prevent  the  electro- 
lytic action,  for  this  does  not  take  place  except  where  the  metallic 
circuit  is  interrupted. 

The  railway  companies  should  be  just  as  much  interested  as  the 
water  departments  in  keeping  the  return  currents  on  the  tracks,  for 
the  wandering  electricity  means  waste  of  power  and  consequent 
loss  of  income.  Well-bonded  rails  and  large  conductors  from  the 
rails  to  the  power  house  will  accomplish  a  great  deal  in  preventing 
electrolysis  and  saving  current.  These  precautions  will  not  do 
everything,  however,  and  where  the  hydrants  are  found  to  be 
strongly  positive  to  the  rails  they  should  be  bonded  with  the  lat- 
ter by  heavy  copper  wires,  or,  in  the  case  of  important  pipes,  the 
latter  should  be  bonded  to  heavy  copper  conductors  leading  di- 
rectly to  the  switchboard  in  the  power  station.  The  trouble 
usually  begins  with  the  service  pipes  and  rarely  occurs  more  than 
a  quarter  of  a  mile  from  the  power  station,  and  these  precautions, 
although  not  absolute  preventatives,  are  fairly  good  remedies.  If 
the  trouble  is  marked,  the  advice  of  an  engineer  should  be  obtained 
at  once  before  the  water  plant  is  seriously  injured.  The  fee  for 
the  advice  is  but  a  trifle  compared  with  the  loss  due  to  the  destruc- 
tion of  the  street  mains. 

Setting  meters  should  always  be  done  by  the  water  department, 
as  previously  mentioned.  There  are  many  methods  of  placing 
them,  which  were  well  summarized  in  1896  in  a  report  of  a  com- 
mittee of  the  American  Water- Works  Association  which  was  sub- 
stantially as  follows:  In  all  cases  a  stop  and  waste  cock  should  be 
placed  between  the  meter  and  street  main  and  a  stop  cock  between 
the  meter  and  the  house  pipe.  This  is  of  great  advantage  in  re- 
moving meters  for  testing  or  repairs.  When  meters  are  set  in  cel- 
lars, they  should  be  placed  as  near  a  wall  as  possible,  to  lessen  the 
liability  of  connections  being  made  ahead  of  the  meter,  and  they 
should  be  accessible  for  reading  or  removal.  Where  there  is  dan- 
ger from  frost,  the  meter  should  be  encased  in  a  wooden  box  and 


WATER-WORKS  MANUAL.  279 

packed  with  sawdust,  mineral  wool  or  other  non-conducting  mater- 
ial. When  it  is  placed  in  sidewalks  or  yards,  it  should  be  set  in  a 
brick  pit  or  an  iron  or  wooden  box,  large  enough  to  allow  its  re- 
moval without  disturbing  the  box.  The  pit  or  box  should  have  an 
iron  cover  with  a  locking  device.  The  meter  should  be  set  deep 
enough  to  avoid  freezing,  and,  if  necessary,  packed  with  sawdust 
or  other  suitable  material.  Extension  dials,  which  bring  the 
counters  to  within  a  few  inches  of  the  surface,  are  a  convenience  in 
taking  the  readings. 

Cleaning  mains  is  usually  accomplished  by  opening  the  blow-offs 
or  hydrants  and  allowing  the  water  to  flush  out  the  sediment. 
The  work  should  be  done  on  sections  of  the  mains,  one  after  the 
other,  so  that  but  a  portion  of  the  consumers  are  affected  at  one 
time.  In  case  ordinary  flushing  will  not  answer,  wooden  balls  are 
sometimes  inserted  in  the  pipe  and  forced  along  by  the  pressure  of 
the  water  to  the  end  of  the  line  to  be  cleaned.  Special  arrange- 
ments must  be  made  for  inserting  and  removing  the  balls.  Mr. 
Charles  Hermany  once  used  5-inch  wooden  cubes  for  this  purpose. 
Lead  plugs  of  different  weights  were  placed  on  opposite  corners  of 
each  cube,  so  as  to  make  it  of  approximately  the  same  weight  as  an 
equal  volume  of  water  or  a  trifle  heavier,  the  object  being  to  have 
the  block  strike  the  bottom  as  well  as  the  top  of  the  pipe. 

What  are  known  as  go-devils  have  also  been  employed  in  a  few 
cities.  According  to  Mr.  Dexter  Brackett  those  used  in  Boston 
consisted  of  a  flexible  central  shaft  about  3^  feet  long,  composed  of 
coiled  steel  springs  connecting  small  castings,  to  which  were 
hinged  two  sets  of  steel  scrapers  arranged  radially  around  the 
shaft  about  12  inches  apart.  The  scrapers  were  kept  against  the 
sides  of  the  pipes  by  coiled  springs,  which  allowed  them  to  turn 
back  to  pass  taps  or  other  firm  obstacles.  Back  of  the  scrapers 
were  two  rubber  pistons,  placed  about  2  feet  apart,  so  as  to  ensure 
a  pressure  011  the  machine  when  it  was  passing  branches.  A  sec- 
tion was  cut  out  of  the  pipe  long  enough  to  receive  the  scraper, 
which  was  then  inserted  and  the  joints  made  with  lead  in  the 
ordinary  manner,  except  that  clamp  sleeves  were  used,  so  that  the 
section  could  be  again  easily  removed  and  the  scraper  inserted  if 
desired.  A  simliar  piece  was  cut  from  the  pipe  at  the  lower  end 
of  the  main  to  be  cleaned,  and  the  scraper  was  forced  through  the 
pipe  by  the  ordinary  water  pressure,  which  varied  from  30  to  45 
pounds. 


280  WATER-WORKS  MANUAL. 

As  occupants  of  buildings  on  the  line  of  the  pipes  were  without 
water  while  the  work  of  cleaning  was  in  progress  and  it  was  not 
thought  advisable  to  pass  the  scrapers  through  valves,  the  pipes 
were  cleaned  in  lengths  averaging  1,000  feet.  The  scraper  gener- 
ally passed  through  this  distance  in  from  three  to  four  minutes. 
In  a  few  instances  it  was  stopped  by  obstructions  in  the  pipe,  the 
one  causing  the  most  trouble  being  lead  which  had  run  into  the 
pipe  at  a  joint.  The  water  issuing  from  the  open  end  of  the 
pipe  was  the  color  of  ink  for  five  to  ten  minutes  after  the  scraper 
had  passed  through,  and  it  was  allowed  to  run  to  waste  until  it 
became  clear;  after  this  the  section  of  the  pipe  was  replaced  and  the 
valves  opened.  Some  difficulty  was  experienced  from  the  stopping 
of  service  pipes  and  house  plumbing  by  rust  forced  into  the  pipes 
by  the  pressure  of  the  water  following  the  scraper,  but  this  diffi- 
culty could  generally  be  overcome  by  applying  a  force  pump  to  the 
house  plumbing  and  forcing  the  obstructions  back  into  the  main. 
The  scraping  doubled  the  discharging  capacity  of  the  pipes. 

By  this  method  the  tubercles  were  removed  from  58,000  feet  of 
6-inch  pipe  at  a  cost  of  14  cents  per  foot,  and  from  20,300  feet  of 
12-inch  pipe  at  a  cost  of  20.6  cents  per  foot.  These  prices  include 
5  cents  per  foot  royalty  for  the  right  to  use  the  scraper. 

The  approximate  capacity  of  service  pipes  is  shown  by  the  ac- 
companying table,  which  is  taken  from  data  compiled  by  the  Bos- 
ton Water  Department. 

Approximate  Discharge  in  Gallons  per  Minute  of  Service  Pipes  of 
Different  Diameters  and  Lengths.  H=Head  in  Feet;  L=Length  of 
Pipe  in  Feet. 


H  equal 

Diameter  of  Pipe 

in  Inches. 

to 

V2 

% 

% 

1 

1% 

1% 

2 

2V2 

3 

10L 

20 

34 

54 

112 

195 

308 

632 

1,100 

1,745 

8L 

18 

30 

49 

100 

175 

275 

566 

988 

1,560 

6L 

15 

26 

42 

87 

151 

238 

488 

855 

1,350 

4L 

12 

22 

34 

71 

123 

195 

400 

700 

1,100 

2L 

9 

15 

24 

50 

87 

138 

283 

494 

780 

1.5  L 

7.5 

13 

21 

43 

76 

119 

250 

428 

675 

L 

6 

11 

17 

35 

62 

97 

200 

350 

555 

L-f-2 

4.5 

7.5 

12 

25 

44 

69 

141 

247 

390 

L-i-4 

3 

5.5 

8.5 

18 

31 

49 

100 

175 

275 

L-f-6 

2.5 

4.5 

7 

14.5 

25 

40 

82 

143 

225 

L-j-8 

2.2 

4 

6 

12.5 

22 

34 

71 

123 

195 

L-f-10 

2.0 

3.5 

5.5 

11 

19 

31 

63 

110 

174 

L-r20 

1.2 

2.2 

3.5 

7 

13 

21 

45 

80 

130 

L-^-40 

0.8 

1.5 

2.2 

5 

9 

14 

30 

54 

90 

In  closing  this  chapter,  the  writer  wishes  to  emphasize  the  im- 
portance of  keeping  clear  records  in  the  office  of  the  water  de- 


WATER-WORKS    MANUAL,  281 

partment  of  every  feature  of  the  administration,  financial  and 
physical.  There  should  be  a  complete  set  of  plans  of  the  works, 
books  showing  the  size  and  exact  location  of  every  pipe,  house  ser- 
vice, hydrant  and  valve,  so  made  out  that  they  can  be  found  im- 
mediately, even  when  the  ground  is  covered  by  snow:  Each  gate 
should  be  located  when  possible  by  measurements  to  at  least  two 
permanent  points. 

In  the  pumping  station,  a  book  should  be  kept  showing  the  time 
of  each  man,  the  number  of  hours  each  pump  runs  and  the  strokes 
or  revolutions  it  makes,  the  amount  of  fuel  used,  the  suction  and 
pressure  gauge  readings  at  half-hour  intervals,  full  data  of  all  fire 
service,  and  the  quantity  of  supplies  received. 

The  financial  books  of  the  department  have  to  be  kept  to  con- 
form with  the  ordinances  under  which  the  department  is  man- 
aged. There  is  no  doubt  that  the  best  method  of  opening  them 
is  first  to  obtain  specimen  sheets  from  departments  of  the  same 
size  which  have  been  organized  for  a  number  of  years,  and,  sec- 
ond>  to  turn  this  material  over  to  the  best  accountant  in  the  com- 
munity with  a  request  to  draw  up  a  set  of  books  fitting  the  local 
conditions.  No  general  forms  can  be  employed  satisfactorily  be- 
cause of  the  variation  in  local  conditions  which  renders  them  but 
partly  useful, 


INDEX. 


Accumulators   on   force   mains 247 

Adits    from    wells 108 

Air 

chambers     155 

on  suction  pipes 117,167 

on    force    mains 248 

and      water-tanks      in      place 

of   standpipes 250 

compressors   158 

for    lifting    water 157 

removing  anchor  ice 177 

in  suction  pipes 155,  178,  271 

wells    116,    271 

valves    on   pipes 208 

Albuminoid   ammonia    19 

Alumina,    sulphate    of 184 

Ammonia 

albuminoid 19 

free     20 

Anabaena     86 

Analyses,    water 19,    135 

sand     186 

Anchor   ice 176,    177,   271 

Artesian    wells 89,    122 

Asphalt    reservoir    linings 230 

Asterionella     86 

Bacteria    .  .    22 

Ball    joints 179,    209 

Bends,   cast-iron 206 

Berms   on   slopes 34 

Blow-offs 208 

Bonds    for    water-works 263 

Book-keeping    281 

Boring    wells 107,    126 

Branches,     cast-iron 206 

Brick    reservoir    lining 229,    233 

Brick    roof    arches 219 

Brickwork,     water-proofing 169 

Brooks,     gauging 17 

Brush     dams 53 

Bucket,    sand 104 

Calking,    stand-pipes 236 

Caps,     cast-iron 206 

Castings,     special 206 

Cast-iron    pipe 204 

Catchment   area 

surveying    9 

discharge    from 12 

flood    discharges 44 

ground    water 90 

Centrifugal    pumps 152 

Channels,    open   paved 214 

Charges   for  water 256,  270 


Check  valves 155,   223 

Chisel   for  hard-pan,   etc 106 

Clarification    of    water 182 

Clay 

for    dams 24 

pipes     214 

Cleaning 

filters     187 

pipes     • 279 

reservoir    sites 84 

sand    68,    192 

Coagulation   before   filtration.  .184,   193 

Compressors,     air 158 

Concrete 

and   asphalt   reservoir   lining 230 

brick    reservoir    lining 229 

in     dams 67 

reservoir     lining 222 

specification     227 

Consumption   of  water 252,   264 

Core  walls 

puddle     31 

masonry     29 

constructing    35 

specification     226 

Crenothrix     136 

Cribs 

dams     54 

filters     176 

intakes     174,    ISO 

Cyclopean    masonry 65 

Dams 

earth     23 

core   walls   for 29 

percolation    through 71 

masonry    48,   61 

rock-fill     79 

timber    51,    52 

Deep    wells 89,    123 

sinking     103 

Diamond    drills 128 

Dickens'    discharge    formula 45 

Differential     pumps 150 

Discharge 

deep    wells 131 

flumes     214 

pipes     198,    280 

services    to    houses 280 

watersheds     45 

wells,     measuring 112 

vitrified    clay    pipe 214 

Distribution  of  water 

districts     209 

mains    256 


284 


INDEX. 


Drilling   wells 107,    126 

Driven    wells 109 

Duplex    pumps 141 

Earth 

backing  of  masonry  dams 70 

dams    22,   224 

percolation    through 71 

excavation    and    embankment..     224 

removal    from    reservoirs 84 

wetting    and    rolling 33 

Effective  size  of  sand  for  filters..  186 

Electric  lighting  plant 16fi,   171 

Electric  motors   for  pumps 146,   153 

Electrolysis     277 

Engines,  gas  and  gasoline. 146,  153,  170 
Evaporation  from  earthworks —  32 
Filters 

crib     176 

galleries     89 

mechanical     192 

sand     185 

Financing    water-works 264 

Fire    protection 252 

streams     258 

Flexible    joints 179,    209 

Floods     44 

Flumes     214 

Fly-wheel     pumps 142 

Foot    valves 154 

Force    mains,    ram   in 248 

Foundations 

pumps     154 

standpipes     239 

Framed    dams 51,     56 

Freshets     44 

Friction 

pipe    196,    256 

hose     260 

Gas  and  gasoline  engines.  .146,  153,  170 

Gate-houses   39,  63,  191,  223 

water-proofing     169 

Gates 

effluent,    from    filters 190 

location    on    pipes 208 

sluice     40 

testing     122 

Gauging     streams 17 

wells     113 

Gravel 

in    dams 26 

filters     188 

reservoir    sites 85 

Gradient,     hydraulic 199 

Ground    water,    see    Chapters    vii-xi. 

Hardness  of  water 21,   137 

Hard-pan     28,     32 

tools  for  sinking  wells  in 106 

Headworks   for   river   supplies —    81 

Hose    253,    260 

Hydrants 

gates    to    control 208 

location     253 

protection    against    freezing 273 

Hydraulic    gradient 199 

Tee,  anchor;  see  Anchor  ice. 

Indian    shovel 105 

Intakes     174 

Joints 

cast-iron    pipe 205,    208 

flexible    179,    209 

Thacher   draw 212 

vitrified   clay   pipe 215 


Lakes,   seasonal   changes 83 

Laying  pipe 120,  179,  208,  211,  215 

Lead   in   pipe  joints 206 

Lift,    air 157 

Lining     reservoirs;     see     Reservoirs, 
lining. 

Masonry 

ashlar     78 

base   for   standpipes 239,   245 

brick    arches 219 

core    walls 29 

dams     61 

gate    chambers 41 

rubble   66,  77,  228 

waste    weirs 48 

water-proofing     167 

Mechanical    filters 192 

Meters     267 

setting     278 

Micro-organisms   affecting  water.    86 

Miser  for  reaming  wells 107 

Mortar 

specification     227 

use  at  freezing  temperatures...    68 

Mixing    concrete 228 

Nitrates  in  water ...20,  135 

Nitrites    20 

Nozzles  for  fire  hose 259 

Odors  in  water 84,  86 

Open  wells 100 

Paving  slopes 226 

Percolation 

through  earth  dams 71 

soil    102 

Pipe 

artesian   well 129 

calculation  of  sizes 196 

cast-iron   204 

cleaning  279 

driven   well 121 

for  air  lifts 156 

in  earth  dams 38 

gate-houses... 41,  63,  223 

laying 120,  208,  211,  215 

protection  against  freezing 214 

repairing    submerged 213 

service    280 

spiral    riveted 203 

standpipe   inlets 239 

steel    203 

street  mains 256 

submerged 179,  209 

suction Ill,  117,  120,  178 

trussed  over  rivers 214 

vitrified   clay 214 

wood 175,  204 

Pitot's  tube  for  well  gauging 113 

Plaster  finish  on  rubble  masonry..  226 

Ponds,   seasonal  changes S 

Power  pumps 145,   170 

Pressure 

regulators  on  pipes 2C 

wind  on  standpipes 235 

Public  uses  of  water 264 

Puddle    24 

core   walls 3 

specification    225 

Pumping  stations 165 

Pumps    13 

air    lift 157 

location  for  wells 11 

relation  to  force  mains 200 

size  affected  by  water  storage..  218 


INDEX.  285 

Quicksand  concrete    226 

handling    35       core  wall 226 

under  a  dam 69       driven  wells 119 

excavation  and  embankment 224 

Rainfall    13       itemized  229 

Ram  in  pipes,  masonry  in  dams 76 

allowance  for 205       mortar   226 

prevention    248        puddle   225 

Reaming  wells 107,  125,  127        reservoir    lining 225 

Regulators,    pressure 209        slope    paving 226 

Repairs  to  submerged  pipe 213       sodding    225 

Reservoirs  standpipes    236 

impounding,  pipes  from 38       water  in  earth  dams 33 

site    23,   64    Spillways    46 

size    14       in  framed  dam 57 

importance  of  clean  bottom 85  see   Weirs,  waste. 

lining,    asphalt 230  Springs 

brick    229       for  water  supplies 92 

concrete    222       in   dam    sites 67,    68 

stone  25,  221    Spring-pole   drilling 127 

sedimentation   183  Sprinkling  earth  before  rolling. 33,  224 

service    218    Stadia  surveys 9,  11 

covering    219    Standpipes    218,   235 

size    256       size    255 

shallow   flowage 84       substitute   for 250 

Rivers  Steam 

crossing  by  pipes 209       consumption  in  pumping 141 

gauging   17       for  removing  anchor  ice 177 

trussed  pipes  over 214  Steel 

Riveting    236       for  standpipes 236 

Rock-fill  dams 79       pipe  203 

Rolling  earth  in  dams 33,  224    Stone  paving  on  slopes 226 

Rotary  drilling  for  wells 128  Storage  of  water  to  develop  catch- 
Rotary  pumps 151       ment   areas 14 

Rubble  masonry 65,  69  Strainers, 

specifications    77,    228       wells  Ill,  112,  115,  121,  129 

Runoff;  see  Catchment  area.  pumps   154 

Ryves'  discharge  formula 45    Street   pipes 256 

Submerged  pipe 179,   209 

Salt  in  mortar 68    Suction  pipe Ill,  117,  120,  154,  178 

Sand  Sulphate  of  alumina 184 

bucket    104  Surface  water;  see  Chapter  i. 

excavating  from  wells 105    Surveys    9 

for  filters 185  Sylvester  process  of  water-proof- 
in   dams 23        ing   masonry 167 

intercepting 80,   167,   217    Synura    86 

jet    105 

pump   110    Taste  of  water,  bad 86 

washing 68,   192    Tees,   cast-iron 206 

Screens  Tests 

for  sand  analysis 186       gates    122 

in  gate-houses 41,  63       pipe  laying 120 

Screw    pumps 151    Thacher  joint 212 

Seasonal  changes  in  lakes 83    Thawing   hydrants 273 

Sedimentation    183       service   pipes 275 

Seed  bag  for  wells 131    Thickness   of  cast-iron   pipe 205 

Separators  on  gang  wells.. 117,  167,  271  Timber 

Service  pipes  dams    52 

discharge   280       for  submerged  work 60 

thawing  275       waste   weir 51 

Service  reservoirs 218,  256    Topographical   surveys 9 

Setting  meters 278    Torpedo  for  shooting  wells 125 

pumps   154    Triplex   pumps.. 149 

Shallow  flowage  in  reservoirs 84    Trussing  for  pipe  crossings 214 

Sheet    piling 35,    70    Tube    wells 89,    109 

Shovel,    Indian 105    Tuberculation  of  pipes 197 

Sieves  for  sand  analysis 186    Turbidity  of  water 183 

Silt  causing  turbidity 182 

Sinking  wells 102,  109,  111,  125    Uniformity  coefficient  of  sand 186 

Sketchboard  for  topography 10    Uroglena    86 

Sleeves,    cast- iron 206 

Slopes  of  earth  dams 34,  225  Valves;  see  Gates. 

Sluice  openings,  size 40       air    208 

Sodding    225       pump    147 

Special    castings 206       reducing   209 

Specifications  Vitrified  clay  pipes 214 

artesian    wells 128    Voids  in  earth 29 

cast-iron  pipe 207    Volvox   86 


286 


INDEX. 


Ward  joints  ..............  ,  ............  211 


68, 


192 
266 


Washing  sand 

Waste  of  water 

Water 
consumption    ..  ...........  251,    264,    270 

ground    ...........................  90,   135 

protection  from  light  ____  ........  219 

meters    ....................  .  .........  268 

percolation  through  earth  dams..  71 
soil    ................................  102 

ram    ........................  ;....205,    248 

surface   ..............................    18 

changes  in  .........................    83 

waste    ...............................  266 

Water-proofing    masonry  ...........  167 

Water-sheds;    see    Catchment    areas. 

Water-towers  .....................  218,    235 

size    .........  .  ..................  255 


Weights  of  pipes  and  castings 206 

Weirs    17 

dams 58 

movable,  in  gate-house 63 

waste,   in  reservoirs... ........    44 

Wells 

air    lift 157 

artesian  and  deep 122 

classification    89 

driven    109 

open   101 

pumps  for 139,   152 

Wood   dams 52 

flumes   211 

pipe  175,  204 

Wind-pressure   235 

Wyckoff   pipe 204 


/E 


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LAMBERT  METER 


Some  Details   of  Water- Works 
Construction* 

By  W.  R.  BILLINGS, 

SUPERINTENDENT  OP  WATER-WORKS  AT  TAUNTON,  MASS. 

With  Illustrations  from  Sketches  by  the  Author* 


INTRODUCTORY  NOTE. 

Some  questions  addressed  to  the  editor  of  THE  ENGINEERING  RECORD  by 
persons  in  the  employ  of  new  water-works  indicated  that  a  short  series  of  practical 
articles  on  the  Details  of  Constructing  a  Water-Works  Plant  would  be  of  value  ;  and, 
at  the  suggestion  of  the  editor,  the  preparation  of  these  papers  was  undertaken  for 
the  columns  of  that  journal.  The  task  has  been  an  easy  and  agreeable  one,  and 
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TABLE  OF  CONTENTS. 


CHAPTER  I.— MAIN  PIPES— 
Materials — Cast-iron  —  Cement-Lined 
Wrought  Iron  —  Salt-Glazed  Clay- 
Thickness  of  Sheet  Metal— Methods 
of  Lining— List  of  Tools— Tool-Box— 
Derrick  —  Calking  Tools  —  Furnace — 
Transportation — Handling  Pipe — Cost 
of  Carting— Distributing  Pipe. 

CHAPTER  II.— FIELD  WORK— 
Engineering  or  None  —  Pipe  Plans — 
Special  Pipe — Laying  out  a  Line — 
Width  and  Depth  of  Trench — Time- 
Keeping  Book— Disposition  of  Dirt- 
Tunneling— Sheet  Piling. 

CHAPTER     III.— TRENCHING     AND 
PIPE-LAYING— 

Caving  —  Tunneling  —  Bell-Holes  — 
Stony  Trenches — Feathers  and  Wedges 
— Blasting — Rocks  and  Water — Lay- 
ing Cast-Iron  Pipe — Derrick  Gang — 
Handling  the  Derrick  —  Skids  —  Ob- 
structions Left  in  Pipes — Laying  Pipe 
in  Quicksand— Cutting  Pipe. 


CHAPTER    IV.— PIPE-LAYING    AND 
JOINT-MAKING— 

Laying  Cement-Lined  Pipe  —  "Mud" 
Bell  and  Spigot— Yarn— Lead— Joint- 
ers—Roll— Calking— Strength  of  Joints 
—Quantity  of  Lead. 

CHAPTER    V.— HYDRANTS,    GATES, 

AND   SPECIALS- 
CHAPTER  VI.— SERVICE  PIPES. 

Definition  —  Materials  —  Lead  vs. 
Wrought  Iron — Tapping  Mains  for 
Services— Diff  ere  at  Joints— Compres- 
sion Union — Cup. 

CHAPTER   VII.— S  E  R  V  I  C  E-PIPES 
AND  METERS— 

Wiped  Joints  and  Cup-Joints — The 
Lawrence  Air-Pump  —  Wire-drawn 
Solder — Weight  of  Lear  Service-Pipe 
—Tapping  Wrought-Iron  Mains— Ser- 
vice-Boxes— Meters. 


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Illustrated  catalogue,  giving  full  detail*,  'ree  to  any  applicant. 


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ARTESIAN  WELL  PUMPS. 

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Cheap'  st   to    operate,   and   have   the 
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cent,  efficiency,  our 
Pump  gave  80  per  cent. 


CATALOG  SHVT  f/PO.V  RLQUBST. 


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Square 
Standard  Dial. 


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THE  BUILDER,  ENGINEERING  RECORD  for  the  best  designs  for  treating  water 
LONDON.  towers  and  stations  with  architectural  and  picture- que  effect, 

with  due  regard  to  economy.  As  a  set  they  are  highly  creditable  to  their  authors 
and  prove  that  such  erections  may  be  made  perfectly  agreeable  in  an  architectural 
sense.  Whether  American  engineers  are  any  better  than  their  English  brethren  in 
regard  to  these  things  we  do  not  know  ;  we  imagine  the  designs  in  this  book  are 
mostly  the  work  of  architects,  but  their  authors  have  the  credit  of  havi-g  shown 
how  the  thing  can  be  done,  and  we  recommend  the  book  to  the  attention  of  English 
engineers." 


Sent  Postpaid,  Bound  in  Boards,  on  Receipt  of  $2,00. 


The  European  Cement  Industry. 

By  FREDERICK  H.  LEWIS, 
M,  Am.  Soc.  G.  E. 

FROM  THE  "Early  in  the  year  1897,  THE  ENGINEERING  RECORD  began 

PUBLISHERS  the  publication  of  a  series  of  articles  upon  the  European  Portland 
NOTE.  Cement  Industry.  The  articles  were  prepared  especially  for  this 

journal  by  Mr.  Frederick  H.  Lewis,  M.  Am.  Soc.  C.  E.,  who  undertook,  in  the  inter- 
est of  this  inquiry,  a  personal  inspection  of  the  important  European  plants,  and  who 
from  his  familiarity  with  the  subject,  was  well  qualified  to  compare  foreign  with 
American  practice.  *  *  *  As  the  issues  containing  the  articles  have  now  been 
exhausted  and  the  demand  for  them  still  continues,  it  has  been  decided  to  repubtfsh 
them  in  this  form,  with  some  additional  illustrations." 

Cloth,  Octavo*     Price,  $J  00,  Postpaid* 


THE  ENGINEERING  RECORD, 

iOO  WILLIAM  STREET,  NEW  YORK. 


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VENTILATION   AND    HEATING. 

By  JOHN  S/  BILLINGS,  A.  RL,  M.  D., 

LL.  D.  Edinb.  and  Harvard.    D.  C.  L.  Oxon.    Member  of  the 
National  Academy  of  Sciences.    Surgeon  U.  8.  Army,  etc. 


FROM  THE  PREFACE. 

IN  preparing  this  volume  my  object  has  bee  a  to  produce  a  book  which  will  not  only 
1  be  useful  to  students  of  architecture  and  engineering,  and  be  convenient  for  refer- 
ence by  those  engaged  in  the  practice  of  these  professions,  but  which  can  also  be  un- 
derstood by  non-professional  men  who  may  be  interested  in  the  important  subjects  of 
which  it  treats;  and  hence  technical  expressions  have  beenavoide  t  as  much  as  poss- 
ible, and  only  the  simplest  formulae  have  been  employed.  It  includes  all  that  is 
practically  important  of  my  book  on  the  Principles  of  Ventilation  and  Heating,  the 
last  edition  of  which  appeared  in  1889;  but  it  is  substantially  a  new  work,  with 
numerous  illustrations  of  recent  practice.  For  many  of  these  I  am  indebted  to  THJJ 
ENGINEERING  RECORD,  in  which  the  descriptions  first  appeared. 

I  am  also  indebted  to  Dr.  A.  C.  Abbott  for  much  valuable  assistance  in  its  prepa- 
ration, and  to  the  architects  and  heating  engineers  who  have  furnished  me  with 
plans  and  information,  and  whose  names  are  mentioned  in  connection  with  the  de- 
scriptions of  the  several  buildings,  etc. ,  referred  to  in  the  text. 

WASHINGTON,  D.  C.  JOHN  S  BIIJJNGS. 

December,  1892. 

TABLE  OF  CONTENTS. 


CHAPTER  I.— Introduction.  Utility  of 
Ventilation. 

CHAPTER  II.— History  and  Literature  of 
Ventilation. 

CHAPTER  III.— The  Atmosphere;  Its 
Chemical  and  Physical  Properties. 

CHAPTER  IV.— Carbonic  Acid. 

CHAPTER  V.— Conditions  Which  Make 
Ventilation  Desirable  or  Necessary. 
Physiology  of  Respiration.  Gaseous  and 
Particulate  Impurities  of  Air.  Sewer 
Air.  Soil  Air.  Dangerous  Gases  and 
Dusts  in  Particular.  Occupations  or 
Processes  of  Manufacture.  Drying 
Rooms. 

CHAPTER  VI.— On  Moisture  in  Air,  and 
Its  Relations  to  Ventilation. 

CHAPTER  VII.— Quantity  of  Air  Re- 
quired for  Ventilation. 

CHAPTER  VIII.— On  the  Forces  Con- 
cerned in  Ventilation. 

CHAPTER  IX.— Examination  and  Testing 
of  Ventilation. 

CHAPTER  X.— Methods  of  Heating. 
Stoves.  Furnaces.  Fireplaces.  Steam 
and  Hot  Water.  Thermostats. 

CHAPTER  XI.— Sources  of  Air  Supply. 
Filtration  of  Air.  Fresh-Air  Flues  and 
Inlets.  By-passes. 

CHAPTER  XII.— Foul  Air  or  Upcast 
Shafts.  Cowls.  Syphons. 

CHAPTER  XIII.— Ventilation  of  Mines. 


CHAPTER  XIV.— Ventilation  of  Hospit- 
als and  Barracks.  Barrack  Hospitals. 
Hospitals  for  Contagious  Diseases.  Bleg- 
dams  Hospital.  U.  S.  Army  Hospitals. 
Cambridge  Hospital.  Hazleton  Hospital. 
Barnes  Hospital.  New  York  Hospital. 
Johns  Hopkins  Hospital.  Hamburg  Hos- 
pital. Insane  Asylums.  Barracks. 

CHAPTER  XV.— Ventilation  of  Halls  of 
Audience  and  Assembly  Rooms.  The 
Houses  of  Parliament.  The  U.  S.  Capi- 
tol. The  New  Sorbonne.  The  New  York 
Music  Hall.  The  Lenox  Lyceum. 

CHAPTER  XVI.— Ventilation  of  Theaters. 
Manchester  Theaters.  Grand  Opera 
House  in  Vienna.  Opera  House  at 
Frankfort-on-the-Main.  Metropolitan 
Opera  House,  New  York.  Madisor 
Square  Theater.  Academy  of  MUSH;, 
Baltimore.  Pueblo  Opera  House.  Em- 
pire Theater,  Philadelphia. 

CHAPTER  XVII.— Ventilation  of 

Churches.  Dr.  Hall's  Church,  New 
York.  Hebrew  Temple,  Keneseth-Israel, 
Philadelphia. 

CHAPTER  XVIII.— Ventilation  of  Schools. 
Bridgeport  School.  Jackson  School,  Min- 
neapolis. Garfield  School,  Chicago.  Bryn 
Mawr  School,  near  'Philadelphia.  Col- 
lege of  Physicians  and  Surgeons,  New 
York. 

CHAPTER  XIX.— Ventilation  of  Dwelling 
Houses. 

CHAPTER  XX.— Ventilation  of  Tunnels, 
Railway  Cars,  Ships,  Shops,  Stables,  Sow- 
ers. Cooling  of  Air.  Conclusion. 


Over  500  Pages.    2*0  Illustrations.    Sent  postpaid  upon  receipt  of  $6.00, 

THE  ENGINEERING  RECORD, 

JOO  WILLIAM  STREET,  NEW  YORK. 


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American   Steam  and  Hot -Water 
Heating  Practice* 

Prom  THE   ENGINEERING    RECORD 
(Prior  to  1887   The  Sanitary  Engineer). 

A  Selected  Reprint  of    Descriptive  Articles,  Questions  and    Answers 
With  Five  Hundred  and  Eighty-Five  Illustrations* 


PREFACE 

ENGINEERING  RECORD  (prior  to  1887  THE  SANITARY 
ENGINEER)  has  for  sixteen  years  made  its  department  of  Steam 
and  Hot- Water  Heating  and  Ventilation  a  prominent  feature.  Besides 
the  weekly  illustrated  descriptions  of  notable  and  interesting  current 
work,  a  great  variety  of  questions  in  this  field  have  been  answered.  In 
1888  Steam-Heat  ng  Problems  was  published.  This  was  a  selection  of 
questions,  answers,  and  descriptions  that  had  been  published  during  the 
preceding  nine  years,  and  dealt  mainly  with  steam-heating.  The  present 
book  is  intended  to  supplement  this  former  publication,  and  includes  a 
selection  of  the  descriptions  of  hot- water,  steam-heating  and  ventilating 
installations  in  the  different  classes  of  buildings  in  the  United  States, 
prepared  by  the  staff  of  THE  ENGINEERING  RECORD,  besides  a  collection 
of  questions  and  answers  on  problems  arising  in  this  department  of 
building  engineering,  covering  the  period  since  18  8,  in  whi.h  the  heat- 
ing of  dwellings  by  hot  water  has  become  popular  in  the  United  States. 
The  favor  with  which  Steam- Heating  Problems  has  been  received  en- 
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ventilating  and  heating  apparatus. 

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GEORQK  ORMROD,  JOHN  DONALDSON,  President, 

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Road  Construction  and  Maintenance 

PRIZE  ESSAYS. 


A  "In  the  year  1890,  THE  ENGINEERING  RECORD  instituted  a  prize  com- 

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P.  North  and  James  Owen,  and  they  give  some  comments  and  criticisms  on  the 
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sor or  county  board  having  charge  of  road  making  and  repairs.  It  will  tell  them 
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GRAVITY  *•  PRESSURE  FILTERS 

of  the  Standard  Types. 
Jewell,  Hyatt,  National,  Warren  and  New  York, 


The  Acknowledged    Standard  of 
Mechanical  Filtration. 

PATENTS   SUSTAINED  BY 
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Our  Filter  Plants  now  in  successful  operation  in  140  cities 

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40-42  W.  Quincy  Street,  CHICAGO,  ILL.     f  26  Cortlandt  Street,  NEW  YORK. 


THIS  BOOK  IS  DUE  ON  THE  LAST  DATE 
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OVERDUE. 


MAR  29  1934 

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